From 79feb6558542b9e7cba2707186b9a29e1a511277 Mon Sep 17 00:00:00 2001 From: doo0301 Date: Wed, 12 May 2021 19:56:58 +0800 Subject: [PATCH 01/36] =?UTF-8?q?=E4=BC=98=E5=8C=96=200102.=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=A0=91=E7=9A=84=E5=B1=82=E5=BA=8F=E9=81=8D=E5=8E=86?= =?UTF-8?q?.md=20Java=E7=89=88=E6=9C=AC=EF=BC=88=E5=A2=9E=E5=8A=A0?= =?UTF-8?q?=E8=BF=AD=E4=BB=A3=E6=96=B9=E5=BC=8F=EF=BC=89?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0102.二叉树的层序遍历.md | 35 +++++++++++++++++------ 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/problems/0102.二叉树的层序遍历.md b/problems/0102.二叉树的层序遍历.md index be2e9dca..0781e01d 100644 --- a/problems/0102.二叉树的层序遍历.md +++ b/problems/0102.二叉树的层序遍历.md @@ -419,18 +419,17 @@ public: Java： -``` Java - - +```Java class Solution { public List> resList=new ArrayList>(); public List> levelOrder(TreeNode root) { - checkFun01(root,0); - + //checkFun01(root,0); + checkFun02(root); + return resList; } - //递归方式 + //DFS--递归方式 public void checkFun01(TreeNode node,Integer deep){ if(node==null) return; deep++; @@ -442,12 +441,33 @@ class Solution { } resList.get(deep-1).add(node.val); - checkFun01(node.left,deep); checkFun01(node.right,deep); } + + //BFS--迭代方式--借助队列 + public void checkFun02(TreeNode node){ + if(node==null) return; + Queue que=new LinkedList(); + que.offer(node); + while(!que.isEmpty()){ + List itemList=new ArrayList(); + int len=que.size(); + while(len>0){ + TreeNode tmpNode=que.poll(); + itemList.add(tmpNode.val); + + if(tmpNode.left!=null) que.offer(tmpNode.left); + if(tmpNode.right!=null) que.offer(tmpNode.right); + len--; + } + + resList.add(itemList); + } + + } ``` @@ -458,7 +478,6 @@ Go： - ----------------------- * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) From 9e58a77df02f27c4d3b1aa373cf48bee6bb660d8 Mon Sep 17 00:00:00 2001 From: Powerstot <77142630+Powerstot@users.noreply.github.com> Date: Wed, 12 May 2021 20:30:32 +0800 Subject: [PATCH 02/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00344.=E5=8F=8D=E8=BD=AC?= =?UTF-8?q?=E5=AD=97=E7=AC=A6=E4=B8=B2=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 添加0344.反转字符串 Java版本 --- problems/0344.反转字符串.md | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/problems/0344.反转字符串.md b/problems/0344.反转字符串.md index ddb9805d..02282355 100644 --- a/problems/0344.反转字符串.md +++ b/problems/0344.反转字符串.md @@ -140,7 +140,21 @@ public: Java： - +```Java +class Solution { + public void reverseString(char[] s) { + int l = 0; + int r = s.length - 1; + while (l < r) { + s[l] ^= s[r]; //构造 a ^ b 的结果，并放在 a 中 + s[r] ^= s[l]; //将 a ^ b 这一结果再 ^ b ，存入b中，此时 b = a, a = a ^ b + s[l] ^= s[r]; //a ^ b 的结果再 ^ a ，存入 a 中，此时 b = a, a = b 完成交换 + l++; + r--; + } + } +} +``` Python： From df60da030660fde4e9c86556140ab28ecf5704d9 Mon Sep 17 00:00:00 2001 From: Powerstot <77142630+Powerstot@users.noreply.github.com> Date: Wed, 12 May 2021 20:55:21 +0800 Subject: [PATCH 03/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00541.=E5=8F=8D=E8=BD=AC?= =?UTF-8?q?=E5=AD=97=E7=AC=A6=E4=B8=B2II=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 添加0541.反转字符串II Java版本 --- problems/0541.反转字符串II.md | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/problems/0541.反转字符串II.md b/problems/0541.反转字符串II.md index 6a84006e..7ca63675 100644 --- a/problems/0541.反转字符串II.md +++ b/problems/0541.反转字符串II.md @@ -101,7 +101,36 @@ public: Java： +```Java +class Solution { + public String reverseStr(String s, int k) { + StringBuffer res = new StringBuffer(); + for (int i = 0; i < s.length(); i += (2 * k)) { + StringBuffer temp = new StringBuffer(); + // 剩余字符大于 k 个，每隔 2k 个字符的前 k 个字符进行反转 + if (i + k <= s.length()) { + // 反转前 k 个字符 + temp.append(s.substring(i, i + k)); + res.append(temp.reverse()); + + // 反转完前 k 个字符之后，如果紧接着还有 k 个字符，则直接加入这 k 个字符 + if (i + 2 * k <= s.length()) { + res.append(s.substring(i + k, i + 2 * k)); + // 不足 k 个字符，则直接加入剩下所有字符 + } else { + res.append(s.substring(i + k, s.length())); + } + continue; + } + // 剩余字符少于 k 个，则将剩余字符全部反转。 + temp.append(s.substring(i, s.length())); + res.append(temp.reverse()); + } + return res.toString(); + } +} +``` Python： From a1a875f6db94728fbad5a3529a7aececce8504b8 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Wed, 12 May 2021 21:01:01 +0800 Subject: [PATCH 04/36] =?UTF-8?q?Update=200226.=E7=BF=BB=E8=BD=AC=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=A0=91.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0226.翻转二叉树.md | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/problems/0226.翻转二叉树.md b/problems/0226.翻转二叉树.md index afc1f144..ec1335c6 100644 --- a/problems/0226.翻转二叉树.md +++ b/problems/0226.翻转二叉树.md @@ -208,8 +208,21 @@ Java： Python： -Go： +```Go +func invertTree(root *TreeNode) *TreeNode { + if root ==nil{ + return nil + } + temp:=root.Left + root.Left=root.Right + root.Right=temp + + invertTree(root.Left) + invertTree(root.Right) + return root +} +``` From 47f30c61217086f3481af66bc9faf19efc02666c Mon Sep 17 00:00:00 2001 From: LehiChiang <1471277588@qq.com> Date: Wed, 12 May 2021 21:01:25 +0800 Subject: [PATCH 05/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00111.=E4=BA=8C=E5=8F=89?= =?UTF-8?q?=E6=A0=91=E7=9A=84=E6=9C=80=E5=B0=8F=E6=B7=B1=E5=BA=A6=20Python?= =?UTF-8?q?=E7=89=88=E6=9C=AC=E3=80=82?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0111.二叉树的最小深度.md | 46 ++++++++++++++++++++++- 1 file changed, 44 insertions(+), 2 deletions(-) diff --git a/problems/0111.二叉树的最小深度.md b/problems/0111.二叉树的最小深度.md index 430cd5d6..6c6b4632 100644 --- a/problems/0111.二叉树的最小深度.md +++ b/problems/0111.二叉树的最小深度.md @@ -195,9 +195,51 @@ public: Java： - Python： +递归法： + +```python +class Solution: + def minDepth(self, root: TreeNode) -> int: + if not root: + return 0 + if not root.left and not root.right: + return 1 + + min_depth = 10**9 + if root.left: + min_depth = min(self.minDepth(root.left), min_depth) # 获得左子树的最小高度 + if root.right: + min_depth = min(self.minDepth(root.right), min_depth) # 获得右子树的最小高度 + return min_depth + 1 +``` + +迭代法： + +```python +class Solution: + def minDepth(self, root: TreeNode) -> int: + if not root: + return 0 + que = deque() + que.append(root) + res = 1 + + while que: + for _ in range(len(que)): + node = que.popleft() + # 当左右孩子都为空的时候，说明是最低点的一层了，退出 + if not node.left and not node.right: + return res + if node.left is not None: + que.append(node.left) + if node.right is not None: + que.append(node.right) + res += 1 + return res +``` + Go： @@ -208,4 +250,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
+
\ No newline at end of file From bd888620e6d14e4b0e2b9393d329c0ee574942c1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E4=B8=80=E6=96=87?= <30338551+YiwenXie@users.noreply.github.com> Date: Wed, 12 May 2021 22:39:37 +0900 Subject: [PATCH 06/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200077.=E7=BB=84?= =?UTF-8?q?=E5=90=88=E4=BC=98=E5=8C=96.md=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0077.组合优化.md | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/problems/0077.组合优化.md b/problems/0077.组合优化.md index 2af123d1..a8a17858 100644 --- a/problems/0077.组合优化.md +++ b/problems/0077.组合优化.md @@ -147,7 +147,33 @@ public: Java： +``` +class Solution { + List> result = new ArrayList<>(); + LinkedList path = new LinkedList<>(); + public List> combine(int n, int k) { + combineHelper(n, k, 1); + return result; + } + /** + * 每次从集合中选取元素，可选择的范围随着选择的进行而收缩，调整可选择的范围，就是要靠startIndex + * @param startIndex 用来记录本层递归的中，集合从哪里开始遍历（集合就是[1,...,n] ）。 + */ + private void combineHelper(int n, int k, int startIndex){ + //终止条件 + if (path.size() == k){ + result.add(new ArrayList<>(path)); + return; + } + for (int i = startIndex; i <= n - (k - path.size()) + 1; i++){ + path.add(i); + combineHelper(n, k, i + 1); + path.removeLast(); + } + } +} +``` Python： From 89142373b97c97f44eb8d0ac6962f0c001925361 Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Wed, 12 May 2021 21:59:18 +0800 Subject: [PATCH 07/36] =?UTF-8?q?Update=200017.=E7=94=B5=E8=AF=9D=E5=8F=B7?= =?UTF-8?q?=E7=A0=81=E7=9A=84=E5=AD=97=E6=AF=8D=E7=BB=84=E5=90=88.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0017.电话号码的字母组合.md | 38 ++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/problems/0017.电话号码的字母组合.md b/problems/0017.电话号码的字母组合.md index 6f51a181..76d5655d 100644 --- a/problems/0017.电话号码的字母组合.md +++ b/problems/0017.电话号码的字母组合.md @@ -240,7 +240,45 @@ public: Java： +```Java +class Solution { + //设置全局列表存储最后的结果 + List list = new ArrayList<>(); + + public List letterCombinations(String digits) { + if (digits == null || digits.length() == 0) { + return list; + } + //初始对应所有的数字，为了直接对应2-9，新增了两个无效的字符串"" + String[] numString = {"", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"}; + //迭代处理 + backTracking(digits, numString, 0); + return list; + + } + + //每次迭代获取一个字符串，所以会设计大量的字符串拼接，所以这里选择更为高效的 StringBuild + StringBuilder temp = new StringBuilder(); + + //比如digits如果为"23",num 为0，则str表示2对应的 abc + public void backTracking(String digits, String[] numString, int num) { + //遍历全部一次记录一次得到的字符串 + if (num == digits.length()) { + list.add(temp.toString()); + return; + } + //str 表示当前num对应的字符串 + String str = numString[digits.charAt(num) - '0']; + for (int i = 0; i < str.length(); i++) { + temp.append(str.charAt(i)); + backTracking(digits, numString, num + 1); + //剔除末尾的继续尝试 + temp.deleteCharAt(temp.length() - 1); + } + } +} +``` Python： From 7c85f8c3377ff86a0c26ed04bcfbf9308dad463c Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Wed, 12 May 2021 22:20:54 +0800 Subject: [PATCH 08/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200017.=E7=94=B5?= =?UTF-8?q?=E8=AF=9D=E5=8F=B7=E7=A0=81=E7=9A=84=E5=AD=97=E6=AF=8D=E7=BB=84?= =?UTF-8?q?=E5=90=88.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0017.电话号码的字母组合.md | 1 - 1 file changed, 1 deletion(-) diff --git a/problems/0017.电话号码的字母组合.md b/problems/0017.电话号码的字母组合.md index 76d5655d..5e856df4 100644 --- a/problems/0017.电话号码的字母组合.md +++ b/problems/0017.电话号码的字母组合.md @@ -242,7 +242,6 @@ public: Java： ```Java class Solution { - //设置全局列表存储最后的结果 List list = new ArrayList<>(); From 6437920758d0ec4fc7c8dc7cf2aa8b0ae9b0b29a Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Wed, 12 May 2021 22:23:51 +0800 Subject: [PATCH 09/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200017.=E7=94=B5?= =?UTF-8?q?=E8=AF=9D=E5=8F=B7=E7=A0=81=E7=9A=84=E5=AD=97=E6=AF=8D=E7=BB=84?= =?UTF-8?q?=E5=90=88.md=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0017.电话号码的字母组合.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/problems/0017.电话号码的字母组合.md b/problems/0017.电话号码的字母组合.md index 5e856df4..f06ed80a 100644 --- a/problems/0017.电话号码的字母组合.md +++ b/problems/0017.电话号码的字母组合.md @@ -242,6 +242,7 @@ public: Java： ```Java class Solution { + //设置全局列表存储最后的结果 List list = new ArrayList<>(); @@ -271,6 +272,7 @@ class Solution { String str = numString[digits.charAt(num) - '0']; for (int i = 0; i < str.length(); i++) { temp.append(str.charAt(i)); + //回溯 backTracking(digits, numString, num + 1); //剔除末尾的继续尝试 temp.deleteCharAt(temp.length() - 1); From 0641e56a7171981a024e108dcac60e8c3a40c854 Mon Sep 17 00:00:00 2001 From: LehiChiang <1471277588@qq.com> Date: Wed, 12 May 2021 22:56:39 +0800 Subject: [PATCH 10/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00225.=E7=94=A8=E9=98=9F?= =?UTF-8?q?=E5=88=97=E5=AE=9E=E7=8E=B0=E6=A0=88/0232.=E7=94=A8=E6=A0=88?= =?UTF-8?q?=E5=AE=9E=E7=8E=B0=E9=98=9F=E5=88=97=20Java=E7=89=88=E6=9C=AC?= =?UTF-8?q?=E3=80=82?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0225.用队列实现栈.md | 53 +++++++++++++++++++++++++- problems/0232.用栈实现队列.md | 59 +++++++++++++++++++++++++++-- 2 files changed, 107 insertions(+), 5 deletions(-) diff --git a/problems/0225.用队列实现栈.md b/problems/0225.用队列实现栈.md index 49b5c62b..4018364a 100644 --- a/problems/0225.用队列实现栈.md +++ b/problems/0225.用队列实现栈.md @@ -154,9 +154,58 @@ public: ## 其他语言版本 - Java： +```java +class MyStack { + + Queue queue1; // 和栈中保持一样元素的队列 + Queue queue2; // 辅助队列 + + /** Initialize your data structure here. */ + public MyStack() { + queue1 = new LinkedList<>(); + queue2 = new LinkedList<>(); + } + + /** Push element x onto stack. */ + public void push(int x) { + queue2.offer(x); // 先放在辅助队列中 + while (!queue1.isEmpty()){ + queue2.offer(queue1.poll()); + } + Queue queueTemp; + queueTemp = queue1; + queue1 = queue2; + queue2 = queueTemp; // 最后交换queue1和queue2，将元素都放到queue1中 + } + + /** Removes the element on top of the stack and returns that element. */ + public int pop() { + return queue1.poll(); // 因为queue1中的元素和栈中的保持一致，所以这个和下面两个的操作只看queue1即可 + } + + /** Get the top element. */ + public int top() { + return queue1.peek(); + } + + /** Returns whether the stack is empty. */ + public boolean empty() { + return queue1.isEmpty(); + } +} + +/** + * Your MyQueue object will be instantiated and called as such: + * MyQueue obj = new MyQueue(); + * obj.push(x); + * int param_2 = obj.pop(); + * int param_3 = obj.peek(); + * boolean param_4 = obj.empty(); + */ +``` + Python： @@ -227,4 +276,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
+
\ No newline at end of file diff --git a/problems/0232.用栈实现队列.md b/problems/0232.用栈实现队列.md index 9907b476..abdc363d 100644 --- a/problems/0232.用栈实现队列.md +++ b/problems/0232.用栈实现队列.md @@ -19,7 +19,7 @@ push(x) -- 将一个元素放入队列的尾部。 pop() -- 从队列首部移除元素。 peek() -- 返回队列首部的元素。 empty() -- 返回队列是否为空。 -  + 示例: @@ -129,9 +129,62 @@ public: ## 其他语言版本 - Java： +```java +class MyQueue { + + Stack stack1; + Stack stack2; + + /** Initialize your data structure here. */ + public MyQueue() { + stack1 = new Stack<>(); // 负责进栈 + stack2 = new Stack<>(); // 负责出栈 + } + + /** Push element x to the back of queue. */ + public void push(int x) { + stack1.push(x); + } + + /** Removes the element from in front of queue and returns that element. */ + public int pop() { + dumpStack1(); + return stack2.pop(); + } + + /** Get the front element. */ + public int peek() { + dumpStack1(); + return stack2.peek(); + } + + /** Returns whether the queue is empty. */ + public boolean empty() { + return stack1.isEmpty() && stack2.isEmpty(); + } + + // 如果stack2为空，那么将stack1中的元素全部放到stack2中 + private void dumpStack1(){ + if (stack2.isEmpty()){ + while (!stack1.isEmpty()){ + stack2.push(stack1.pop()); + } + } + } +} + +/** + * Your MyQueue object will be instantiated and called as such: + * MyQueue obj = new MyQueue(); + * obj.push(x); + * int param_2 = obj.pop(); + * int param_3 = obj.peek(); + * boolean param_4 = obj.empty(); + */ +``` + Python： @@ -145,4 +198,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
+
\ No newline at end of file From ff99632a50c45b2e50549ac6ba878ddc4e48b2b1 Mon Sep 17 00:00:00 2001 From: LiangDazhu <42199191+LiangDazhu@users.noreply.github.com> Date: Wed, 12 May 2021 23:19:18 +0800 Subject: [PATCH 11/36] =?UTF-8?q?Update=200053.=E6=9C=80=E5=A4=A7=E5=AD=90?= =?UTF-8?q?=E5=BA=8F=E5=92=8C.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Added python version code --- problems/0053.最大子序和.md | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/problems/0053.最大子序和.md b/problems/0053.最大子序和.md index b8a9d748..05c08a66 100644 --- a/problems/0053.最大子序和.md +++ b/problems/0053.最大子序和.md @@ -142,7 +142,19 @@ Java： Python： - +```python +class Solution: + def maxSubArray(self, nums: List[int]) -> int: + result = -float('inf') + count = 0 + for i in range(len(nums)): + count += nums[i] + if count > result: + result = count + if count <= 0: + count = 0 + return result +``` Go： From 8314c1cf082f83de674f7e2779eba8fe74972422 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 09:03:10 +0800 Subject: [PATCH 12/36] =?UTF-8?q?Update=200019.=E5=88=A0=E9=99=A4=E9=93=BE?= =?UTF-8?q?=E8=A1=A8=E7=9A=84=E5=80=92=E6=95=B0=E7=AC=ACN=E4=B8=AA?= =?UTF-8?q?=E8=8A=82=E7=82=B9.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...0019.删除链表的倒数第N个节点.md | 21 +++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/problems/0019.删除链表的倒数第N个节点.md b/problems/0019.删除链表的倒数第N个节点.md index 3b6dde1e..3b89dabd 100644 --- a/problems/0019.删除链表的倒数第N个节点.md +++ b/problems/0019.删除链表的倒数第N个节点.md @@ -112,7 +112,28 @@ class Solution { } } ``` +Go: +```Go +func removeNthFromEnd(head *ListNode, n int) *ListNode { + result:=&ListNode{} + result.Next=head + var pre *ListNode + cur:=result + i:=1 + for head!=nil{ + if i>=n{ + pre=cur + cur=cur.Next + } + head=head.Next + i++ + } + pre.Next=pre.Next.Next + return result.Next + +} +``` ----------------------- * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) From bff058e3c07dbc55a8110fbd08cbeaba24b8d0d3 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 09:24:19 +0800 Subject: [PATCH 13/36] =?UTF-8?q?Update=200015.=E4=B8=89=E6=95=B0=E4=B9=8B?= =?UTF-8?q?=E5=92=8C.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0015.三数之和.md | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/problems/0015.三数之和.md b/problems/0015.三数之和.md index 55e22887..96dc1ac3 100644 --- a/problems/0015.三数之和.md +++ b/problems/0015.三数之和.md @@ -221,6 +221,40 @@ Python： Go： +```Go +func threeSum(nums []int)[][]int{ + sort.Ints(nums) + res:=[][]int{} + + for i:=0;i0{ + break + } + if i>0&&n1==nums[i-1]{ + continue + } + l,r:=i+1,len(nums)-1 + for l Date: Thu, 13 May 2021 09:32:54 +0800 Subject: [PATCH 14/36] =?UTF-8?q?Update=200198.=E6=89=93=E5=AE=B6=E5=8A=AB?= =?UTF-8?q?=E8=88=8D.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0198.打家劫舍.md | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/problems/0198.打家劫舍.md b/problems/0198.打家劫舍.md index b9ccec45..c64648ad 100644 --- a/problems/0198.打家劫舍.md +++ b/problems/0198.打家劫舍.md @@ -117,6 +117,33 @@ Python： Go： +```Go +func rob(nums []int) int { + if len(nums)<1{ + return 0 + } + if len(nums)==1{ + return nums[0] + } + if len(nums)==2{ + return max(nums[0],nums[1]) + } + dp :=make([]int,len(nums)) + dp[0]=nums[0] + dp[1]=max(nums[0],nums[1]) + for i:=2;ib{ + return a + } + return b +} +``` From 7c8cb23ce5865e4485915491a2302168fc112aff Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:37:33 +0800 Subject: [PATCH 15/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=E5=89=91=E6=8C=87Offer?= =?UTF-8?q?05.=E6=9B=BF=E6=8D=A2=E7=A9=BA=E6=A0=BC.md=20Java=E7=89=88?= =?UTF-8?q?=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/剑指Offer05.替换空格.md | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/problems/剑指Offer05.替换空格.md b/problems/剑指Offer05.替换空格.md index 7881adf3..5f89241b 100644 --- a/problems/剑指Offer05.替换空格.md +++ b/problems/剑指Offer05.替换空格.md @@ -129,7 +129,26 @@ for (int i = 0; i < a.size(); i++) { Java： - +```Java +//使用一个新的对象，复制 str，复制的过程对其判断，是空格则替换，否则直接复制，类似于数组复制 +public static String replaceSpace(StringBuffer str) { + if (str == null) { + return null; + } + //选用 StringBuilder 单线程使用，比较快，选不选都行 + StringBuilder sb = new StringBuilder(); + //使用 sb 逐个复制 str ，碰到空格则替换，否则直接复制 + for (int i = 0; i < str.length(); i++) { + //str.charAt(i) 为 char 类型，为了比较需要将其转为和 " " 相同的字符串类型 + if (" ".equals(String.valueOf(str.charAt(i)))){ + sb.append("%20"); + } else { + sb.append(str.charAt(i)); + } + } + return sb.toString(); + } +``` Python： From 50f42c90ebb8ff078256414b731b533a54d0abbb Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 09:39:02 +0800 Subject: [PATCH 16/36] =?UTF-8?q?Update=200053.=E6=9C=80=E5=A4=A7=E5=AD=90?= =?UTF-8?q?=E5=BA=8F=E5=92=8C.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0053.最大子序和.md | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/problems/0053.最大子序和.md b/problems/0053.最大子序和.md index b8a9d748..e6d3f1c8 100644 --- a/problems/0053.最大子序和.md +++ b/problems/0053.最大子序和.md @@ -145,8 +145,29 @@ Python： Go： +```Go +func maxSubArray(nums []int) int { + if len(nums)<1{ + return 0 + } + dp:=make([]int,len(nums)) + result:=nums[0] + dp[0]=nums[0] + for i:=1;ib{ + return a + }else{ + return b + } +} +``` ----------------------- From 02e9ed76bf30a62393768785e643e7139ee8d360 Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:40:40 +0800 Subject: [PATCH 17/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A01047.=E5=88=A0=E9=99=A4?= =?UTF-8?q?=E5=AD=97=E7=AC=A6=E4=B8=B2=E4=B8=AD=E7=9A=84=E6=89=80=E6=9C=89?= =?UTF-8?q?=E7=9B=B8=E9=82=BB=E9=87=8D=E5=A4=8D=E9=A1=B9=20Java=20?= =?UTF-8?q?=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...除字符串中的所有相邻重复项.md | 23 ++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/problems/1047.删除字符串中的所有相邻重复项.md b/problems/1047.删除字符串中的所有相邻重复项.md index 7a06f02d..d5a8c4ed 100644 --- a/problems/1047.删除字符串中的所有相邻重复项.md +++ b/problems/1047.删除字符串中的所有相邻重复项.md @@ -122,7 +122,28 @@ public: Java： - +```Java +class Solution { + public String removeDuplicates(String S) { + Deque deque = new LinkedList<>(); + char ch; + for (int i = 0; i < S.length(); i++) { + ch = S.charAt(i); + if (deque.isEmpty() || deque.peek() != ch) { + deque.push(ch); + } else { + deque.pop(); + } + } + String str = ""; + //剩余的元素即为不重复的元素 + while (!deque.isEmpty()) { + str = deque.pop() + str; + } + return str; + } +} +``` Python： From c19fcf588dd4c07c60de90122a2196b4ebb80e50 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 09:43:05 +0800 Subject: [PATCH 18/36] =?UTF-8?q?Update=200070.=E7=88=AC=E6=A5=BC=E6=A2=AF?= =?UTF-8?q?.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0070.爬楼梯.md | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/problems/0070.爬楼梯.md b/problems/0070.爬楼梯.md index 6ae6adc7..f0a08f99 100644 --- a/problems/0070.爬楼梯.md +++ b/problems/0070.爬楼梯.md @@ -230,7 +230,20 @@ class Solution: ``` Go： - +```Go +func climbStairs(n int) int { + if n==1{ + return 1 + } + dp:=make([]int,n+1) + dp[1]=1 + dp[2]=2 + for i:=3;i<=n;i++{ + dp[i]=dp[i-1]+dp[i-2] + } + return dp[n] +} +``` From cbaaa6398ae5a3275728efd446c5a03701bff7bd Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:43:25 +0800 Subject: [PATCH 19/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00239.=E6=BB=91=E5=8A=A8?= =?UTF-8?q?=E7=AA=97=E5=8F=A3=E6=9C=80=E5=A4=A7=E5=80=BC=20Java=E7=89=88?= =?UTF-8?q?=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0239.滑动窗口最大值.md | 53 ++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/problems/0239.滑动窗口最大值.md b/problems/0239.滑动窗口最大值.md index 709fa09e..781bfa6f 100644 --- a/problems/0239.滑动窗口最大值.md +++ b/problems/0239.滑动窗口最大值.md @@ -207,7 +207,60 @@ public: Java： +```Java +//自定义数组 +class MyQueue { + Deque deque = new LinkedList<>(); + //弹出元素时，比较当前要弹出的数值是否等于队列出口的数值，如果相等则弹出 + //同时判断队列当前是否为空 + void poll(int val) { + if (!deque.isEmpty() && val == deque.peek()) { + deque.poll(); + } + } + //添加元素时，如果要添加的元素大于入口处的元素，就将入口元素弹出 + //保证队列元素单调递减 + //比如此时队列元素3,1，2将要入队，比1大，所以1弹出，此时队列：3,2 + void add(int val) { + while (!deque.isEmpty() && val > deque.getLast()) { + deque.removeLast(); + } + deque.add(val); + } + //队列队顶元素始终为最大值 + int peek() { + return deque.peek(); + } +} +class Solution { + public int[] maxSlidingWindow(int[] nums, int k) { + if (nums.length == 1) { + return nums; + } + int len = nums.length - k + 1; + //存放结果元素的数组 + int[] res = new int[len]; + int num = 0; + //自定义队列 + MyQueue myQueue = new MyQueue(); + //先将前k的元素放入队列 + for (int i = 0; i < k; i++) { + myQueue.add(nums[i]); + } + res[num++] = myQueue.peek(); + for (int i = k; i < nums.length; i++) { + //滑动窗口移除最前面的元素，移除是判断该元素是否放入队列 + myQueue.poll(nums[i - k]); + //滑动窗口加入最后面的元素 + myQueue.add(nums[i]); + //记录对应的最大值 + res[num++] = myQueue.peek(); + } + return res; + } +} +``` Python： From b105b72870325cf931c8974cfc3badaa566cd054 Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:45:18 +0800 Subject: [PATCH 20/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00376.=E6=91=86=E5=8A=A8?= =?UTF-8?q?=E5=BA=8F=E5=88=97=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0376.摆动序列.md | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/problems/0376.摆动序列.md b/problems/0376.摆动序列.md index 6ae76526..fa90142d 100644 --- a/problems/0376.摆动序列.md +++ b/problems/0376.摆动序列.md @@ -111,7 +111,31 @@ public: Java： - +```Java +class Solution { + public int wiggleMaxLength(int[] nums) { + if (nums == null || nums.length <= 1) { + return nums.length; + } + //当前差值 + int curDiff = 0; + //上一个差值 + int preDiff = 0; + int count = 1; + for (int i = 1; i < nums.length; i++) { + //得到当前差值 + curDiff = nums[i] - nums[i - 1]; + //如果当前差值和上一个差值为一正一负 + //等于0的情况表示初始时的preDiff + if ((curDiff > 0 && preDiff <= 0) || (curDiff < 0 && preDiff >= 0)) { + count++; + preDiff = curDiff; + } + } + return count; + } +} +``` Python： From 51501e7b3574bab18bd3c2a8f8a314fd0a628546 Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:46:24 +0800 Subject: [PATCH 21/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00279.=E5=AE=8C=E5=85=A8?= =?UTF-8?q?=E5=B9=B3=E6=96=B9=E6=95=B0=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0279.完全平方数.md | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/problems/0279.完全平方数.md b/problems/0279.完全平方数.md index 39260926..d72e9099 100644 --- a/problems/0279.完全平方数.md +++ b/problems/0279.完全平方数.md @@ -159,7 +159,28 @@ public: Java： - +```Java +class Solution { + public int numSquares(int n) { + int max = Integer.MAX_VALUE; + int[] dp = new int[n + 1]; + //初始化 + for (int j = 0; j <= n; j++) { + dp[j] = max; + } + //当和为0时，组合的个数为0 + dp[0] = 0; + for (int i = 1; i * i <= n; i++) { + for (int j = i * i; j <= n; j++) { + if (dp[j - i * i] != max) { + dp[j] = Math.min(dp[j], dp[j - i * i] + 1); + } + } + } + return dp[n]; + } +} +``` Python： From 4b5f5b28c56a51deae5713040a1f16548340b287 Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:47:49 +0800 Subject: [PATCH 22/36] =?UTF-8?q?Update=200096.=E4=B8=8D=E5=90=8C=E7=9A=84?= =?UTF-8?q?=E4=BA=8C=E5=8F=89=E6=90=9C=E7=B4=A2=E6=A0=91.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 添加0096.不同的二叉搜索树 Java版本 --- problems/0096.不同的二叉搜索树.md | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/problems/0096.不同的二叉搜索树.md b/problems/0096.不同的二叉搜索树.md index 2764277c..98c993e4 100644 --- a/problems/0096.不同的二叉搜索树.md +++ b/problems/0096.不同的二叉搜索树.md @@ -165,7 +165,26 @@ public: Java： - +```Java +class Solution { + public int numTrees(int n) { + //初始化 dp 数组 + int[] dp = new int[n + 1]; + //初始化0个节点和1个节点的情况 + dp[0] = 1; + dp[1] = 1; + //遍历 + for (int i = 2; i <= n; i++) { + for (int j = 1; j <= i; j++) { + //对于第i个节点，需要考虑1作为根节点直到i作为根节点的情况，所以需要累加 + //一共i个节点，对于根节点j时,左子树的节点个数为j-1，右子树的节点个数为i-j + dp[i] += dp[j - 1] * dp[i - j]; + } + } + return dp[n]; + } +} +``` Python： From 6db6a4c69a318b4ae9e79ae49d41f9ccc2918b9c Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:48:45 +0800 Subject: [PATCH 23/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00096.=E4=B8=8D=E5=90=8C?= =?UTF-8?q?=E7=9A=84=E4=BA=8C=E5=8F=89=E6=90=9C=E7=B4=A2=E6=A0=91=20Java?= =?UTF-8?q?=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0096.不同的二叉搜索树.md | 1 - 1 file changed, 1 deletion(-) diff --git a/problems/0096.不同的二叉搜索树.md b/problems/0096.不同的二叉搜索树.md index 98c993e4..7dea8fb0 100644 --- a/problems/0096.不同的二叉搜索树.md +++ b/problems/0096.不同的二叉搜索树.md @@ -173,7 +173,6 @@ class Solution { //初始化0个节点和1个节点的情况 dp[0] = 1; dp[1] = 1; - //遍历 for (int i = 2; i <= n; i++) { for (int j = 1; j <= i; j++) { //对于第i个节点，需要考虑1作为根节点直到i作为根节点的情况，所以需要累加 From d2f98708a7fe980634f7e5f699e5f77c63671110 Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:50:19 +0800 Subject: [PATCH 24/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00131.=E5=88=86=E5=89=B2?= =?UTF-8?q?=E5=9B=9E=E6=96=87=E4=B8=B2=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0131.分割回文串.md | 39 ++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/problems/0131.分割回文串.md b/problems/0131.分割回文串.md index 01ff35c5..9c86a3bc 100644 --- a/problems/0131.分割回文串.md +++ b/problems/0131.分割回文串.md @@ -250,7 +250,46 @@ public: Java： +```Java +class Solution { + List> lists = new ArrayList<>(); + Deque deque = new LinkedList<>(); + public List> partition(String s) { + backTracking(s, 0); + return lists; + } + + private void backTracking(String s, int startIndex) { + //如果起始位置大于s的大小，说明找到了一组分割方案 + if (startIndex >= s.length()) { + lists.add(new ArrayList(deque)); + return; + } + for (int i = startIndex; i < s.length(); i++) { + //如果是回文子串，则记录 + if (isPalindrome(s, startIndex, i)) { + String str = s.substring(startIndex, i + 1); + deque.addLast(str); + } else { + continue; + } + //起始位置后移，保证不重复 + backTracking(s, i + 1); + deque.removeLast(); + } + } + //判断是否是回文串 + private boolean isPalindrome(String s, int startIndex, int end) { + for (int i = startIndex, j = end; i < j; i++, j--) { + if (s.charAt(i) != s.charAt(j)) { + return false; + } + } + return true; + } +} +``` Python： From e81255596869081d0f50e78ea9e5e630ae51fa2a Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:51:51 +0800 Subject: [PATCH 25/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00020.=E6=9C=89=E6=95=88?= =?UTF-8?q?=E7=9A=84=E6=8B=AC=E5=8F=B7=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0020.有效的括号.md | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/problems/0020.有效的括号.md b/problems/0020.有效的括号.md index f2d78ade..4dae7072 100644 --- a/problems/0020.有效的括号.md +++ b/problems/0020.有效的括号.md @@ -138,7 +138,31 @@ public: Java： - +```Java +class Solution { + public boolean isValid(String s) { + Deque deque = new LinkedList<>(); + char ch; + for (int i = 0; i < s.length(); i++) { + ch = s.charAt(i); + //碰到左括号，就把相应的右括号入栈 + if (ch == '(') { + deque.push(')'); + }else if (ch == '{') { + deque.push('}'); + }else if (ch == '[') { + deque.push(']'); + } else if (deque.isEmpty() || deque.peek() != ch) { + return false; + }else {//如果是右括号判断是否和栈顶元素匹配 + deque.pop(); + } + } + //最后判断栈中元素是否匹配 + return deque.isEmpty(); + } +} +``` Python： ```python3 From ce7776d91c5263ab04dc459ef9248849657aee1e Mon Sep 17 00:00:00 2001 From: nanhuaibeian <49868746+nanhuaibeian@users.noreply.github.com> Date: Thu, 13 May 2021 09:53:02 +0800 Subject: [PATCH 26/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00349.=E4=B8=A4=E4=B8=AA?= =?UTF-8?q?=E6=95=B0=E7=BB=84=E7=9A=84=E4=BA=A4=E9=9B=86=20Java=E7=89=88?= =?UTF-8?q?=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0349.两个数组的交集.md | 30 ++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/problems/0349.两个数组的交集.md b/problems/0349.两个数组的交集.md index c196b467..75ef9061 100644 --- a/problems/0349.两个数组的交集.md +++ b/problems/0349.两个数组的交集.md @@ -75,7 +75,37 @@ public: Java： +```Java +import java.util.HashSet; +import java.util.Set; +class Solution { + public int[] intersection(int[] nums1, int[] nums2) { + if (nums1 == null || nums1.length == 0 || nums2 == null || nums2.length == 0) { + return new int[0]; + } + Set set1 = new HashSet<>(); + Set resSet = new HashSet<>(); + //遍历数组1 + for (int i : nums1) { + set1.add(i); + } + //遍历数组2的过程中判断哈希表中是否存在该元素 + for (int i : nums2) { + if (set1.contains(i)) { + resSet.add(i); + } + } + int[] resArr = new int[resSet.size()]; + int index = 0; + //将结果几何转为数组 + for (int i : resSet) { + resArr[index++] = i; + } + return resArr; + } +} +``` Python： From 298ccb13b315ff392af61ad2dc37c2214b3d3923 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 10:07:16 +0800 Subject: [PATCH 27/36] =?UTF-8?q?Update=200450.=E5=88=A0=E9=99=A4=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=90=9C=E7=B4=A2=E6=A0=91=E4=B8=AD=E7=9A=84=E8=8A=82?= =?UTF-8?q?=E7=82=B9.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../0450.删除二叉搜索树中的节点.md | 38 +++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/problems/0450.删除二叉搜索树中的节点.md b/problems/0450.删除二叉搜索树中的节点.md index ed0cb9d7..6e38b4fe 100644 --- a/problems/0450.删除二叉搜索树中的节点.md +++ b/problems/0450.删除二叉搜索树中的节点.md @@ -257,6 +257,44 @@ Python： Go： +```Go +func deleteNode(root *TreeNode, key int) *TreeNode { + if root==nil{ + return nil + } + if keyroot.Val{ + root.Right=deleteNode(root.Right,key) + return root + } + if root.Right==nil{ + return root.Left + } + if root.Left==nil{ + return root.Right + } + minnode:=root.Right + for minnode.Left!=nil{ + minnode=minnode.Left + } + root.Val=minnode.Val + root.Right=deleteNode1(root.Right) + return root +} + +func deleteNode1(root *TreeNode)*TreeNode{ + if root.Left==nil{ + pRight:=root.Right + root.Right=nil + return pRight + } + root.Left=deleteNode1(root.Left) + return root +} +``` From 3e60ed1895ffed5834163a6562f07e11b07ed84c Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 10:10:53 +0800 Subject: [PATCH 28/36] =?UTF-8?q?Update=200110.=E5=B9=B3=E8=A1=A1=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=A0=91.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0110.平衡二叉树.md | 35 +++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/problems/0110.平衡二叉树.md b/problems/0110.平衡二叉树.md index 5d55910c..919ec7c7 100644 --- a/problems/0110.平衡二叉树.md +++ b/problems/0110.平衡二叉树.md @@ -361,7 +361,40 @@ Python： Go： - +```Go +func isBalanced(root *TreeNode) bool { + if root==nil{ + return true + } + if !isBalanced(root.Left) || !isBalanced(root.Right){ + return false + } + LeftH:=maxdepth(root.Left)+1 + RightH:=maxdepth(root.Right)+1 + if abs(LeftH-RightH)>1{ + return false + } + return true +} +func maxdepth(root *TreeNode)int{ + if root==nil{ + return 0 + } + return max(maxdepth(root.Left),maxdepth(root.Right))+1 +} +func max(a,b int)int{ + if a>b{ + return a + } + return b +} +func abs(a int)int{ + if a<0{ + return -a + } + return a +} +``` From f9adafdbcdedfc9fb826ef51b8cf0e58aeaf3e50 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 10:19:25 +0800 Subject: [PATCH 29/36] =?UTF-8?q?Update=200098.=E9=AA=8C=E8=AF=81=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=90=9C=E7=B4=A2=E6=A0=91.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0098.验证二叉搜索树.md | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/problems/0098.验证二叉搜索树.md b/problems/0098.验证二叉搜索树.md index baa3f435..ddd634b4 100644 --- a/problems/0098.验证二叉搜索树.md +++ b/problems/0098.验证二叉搜索树.md @@ -260,7 +260,25 @@ Python： Go： +```Go +import "math" +func isValidBST(root *TreeNode) bool { + if root == nil { + return true + } + return isBST(root, math.MinInt64, math.MaxFloat64) +} +func isBST(root *TreeNode, min, max int) bool { + if root == nil { + return true + } + if min >= root.Val || max <= root.Val { + return false + } + return isBST(root.Left, min, root.Val) && isBST(root.Right, root.Val, max) +} +``` From fe716189caa4fe32a43795219ba157a5c2359692 Mon Sep 17 00:00:00 2001 From: simonhancrew <597494370@qq.com> Date: Thu, 13 May 2021 10:34:16 +0800 Subject: [PATCH 30/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00027.=E7=A7=BB=E9=99=A4?= =?UTF-8?q?=E5=85=83=E7=B4=A0=20Python3=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0027.移除元素.md | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/problems/0027.移除元素.md b/problems/0027.移除元素.md index 144cd5be..959474fc 100644 --- a/problems/0027.移除元素.md +++ b/problems/0027.移除元素.md @@ -124,9 +124,19 @@ public: Java： - Python： +```python +class Solution: + def removeElement(self, nums: List[int], val: int) -> int: + i,n = 0,len(nums) + for j in range(n): + if nums[j] != val: + nums[i] = nums[j] + i += 1 + return i +``` + Go： ```go @@ -162,4 +172,4 @@ var removeElement = (nums, val) => { * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
+
\ No newline at end of file From 01c5d7a8d8461a56fc650117550970f4ca59cae3 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 12:53:02 +0800 Subject: [PATCH 31/36] =?UTF-8?q?Update=200078.=E5=AD=90=E9=9B=86.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0078.子集.md | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/problems/0078.子集.md b/problems/0078.子集.md index 8c68843d..139d0ed5 100644 --- a/problems/0078.子集.md +++ b/problems/0078.子集.md @@ -183,7 +183,28 @@ Python： Go： - +```Go +var res [][]int +func subset(nums []int) [][]int { + res = make([][]int, 0) + sort.Ints(nums) + Dfs([]int{}, nums, 0) + return res +} +func Dfs(temp, nums []int, start int){ + tmp := make([]int, len(temp)) + copy(tmp, temp) + res = append(res, tmp) + for i := start; i < len(nums); i++{ + //if i>start&&nums[i]==nums[i-1]{ + // continue + //} + temp = append(temp, nums[i]) + Dfs(temp, nums, i+1) + temp = temp[:len(temp)-1] + } +} +``` From 8f6ad6641e32a3c5a46895e805a8d0cb3b97e763 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 13:01:07 +0800 Subject: [PATCH 32/36] =?UTF-8?q?Update=200344.=E5=8F=8D=E8=BD=AC=E5=AD=97?= =?UTF-8?q?=E7=AC=A6=E4=B8=B2.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0344.反转字符串.md | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/problems/0344.反转字符串.md b/problems/0344.反转字符串.md index ddb9805d..c2f16794 100644 --- a/problems/0344.反转字符串.md +++ b/problems/0344.反转字符串.md @@ -146,6 +146,17 @@ Python： Go： +```Go +func reverseString(s []byte) { + left:=0 + right:=len(s)-1 + for left Date: Thu, 13 May 2021 13:30:55 +0800 Subject: [PATCH 33/36] update 0404 --- problems/0101.对称二叉树.md | 8 ++++-- problems/0110.平衡二叉树.md | 8 ++++-- problems/0404.左叶子之和.md | 45 +++++++++++++++++++++++++++++++- 3 files changed, 56 insertions(+), 5 deletions(-) diff --git a/problems/0101.对称二叉树.md b/problems/0101.对称二叉树.md index 561d0470..b9e203e8 100644 --- a/problems/0101.对称二叉树.md +++ b/problems/0101.对称二叉树.md @@ -253,9 +253,13 @@ public: ## 其他语言版本 - Java： +```java +``` + + + Python： @@ -284,4 +288,4 @@ const check = (leftPtr, rightPtr) => { * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
+
\ No newline at end of file diff --git a/problems/0110.平衡二叉树.md b/problems/0110.平衡二叉树.md index 5d55910c..ee215a68 100644 --- a/problems/0110.平衡二叉树.md +++ b/problems/0110.平衡二叉树.md @@ -353,9 +353,13 @@ public: ## 其他语言版本 - Java： +```java +``` + + + Python： @@ -369,4 +373,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
+
\ No newline at end of file diff --git a/problems/0404.左叶子之和.md b/problems/0404.左叶子之和.md index 8ff2b320..da4ed666 100644 --- a/problems/0404.左叶子之和.md +++ b/problems/0404.左叶子之和.md @@ -159,9 +159,51 @@ public: ## 其他语言版本 - Java： +**递归** + +```java +class Solution { + public int sumOfLeftLeaves(TreeNode root) { + if (root == null) return 0; + int leftValue = sumOfLeftLeaves(root.left); // 左 + int rightValue = sumOfLeftLeaves(root.right); // 右 + + int midValue = 0; + if (root.left != null && root.left.left == null && root.left.right == null) { // 中 + midValue = root.left.val; + } + int sum = midValue + leftValue + rightValue; + return sum; + } +} +``` + +**迭代** + +```java +class Solution { + public int sumOfLeftLeaves(TreeNode root) { + if (root == null) return 0; + Stack stack = new Stack<> (); + stack.add(root); + int result = 0; + while (!stack.isEmpty()) { + TreeNode node = stack.pop(); + if (node.left != null && node.left.left == null && node.left.right == null) { + result += node.left.val; + } + if (node.right != null) stack.add(node.right); + if (node.left != null) stack.add(node.left); + } + return result; + } +} +``` + + + Python： @@ -176,3 +218,4 @@ Go： * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
+ From a1b5896b69d8d927ffb58d2d46bbc11eca57e3bf Mon Sep 17 00:00:00 2001 From: Tiansheng Sui Date: Wed, 12 May 2021 22:42:44 -0700 Subject: [PATCH 34/36] =?UTF-8?q?=E6=B7=BB=E5=8A=A00035.=E6=90=9C=E7=B4=A2?= =?UTF-8?q?=E6=8F=92=E5=85=A5=E4=BD=8D=E7=BD=AEPython3=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0035.搜索插入位置.md | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/problems/0035.搜索插入位置.md b/problems/0035.搜索插入位置.md index c351e365..e891e3c5 100644 --- a/problems/0035.搜索插入位置.md +++ b/problems/0035.搜索插入位置.md @@ -237,6 +237,22 @@ class Solution { Python： +```python3 +class Solution: + def searchInsert(self, nums: List[int], target: int) -> int: + left, right = 0, len(nums) - 1 + + while left <= right: + middle = (left + right) // 2 + + if nums[middle] < target: + left = middle + 1 + elif nums[middle] > target: + right = middle - 1 + else: + return middle + return right + 1 +``` Go： From 8b30d5d1a72c6516c3a470256ca28e8f55274faa Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Thu, 13 May 2021 14:24:30 +0800 Subject: [PATCH 35/36] =?UTF-8?q?Update=200020.=E6=9C=89=E6=95=88=E7=9A=84?= =?UTF-8?q?=E6=8B=AC=E5=8F=B7.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0020.有效的括号.md | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/problems/0020.有效的括号.md b/problems/0020.有效的括号.md index f2d78ade..ba50ad21 100644 --- a/problems/0020.有效的括号.md +++ b/problems/0020.有效的括号.md @@ -157,7 +157,26 @@ class Solution: ``` Go： +```Go +func isValid(s string) bool { + hash := map[byte]byte{')':'(', ']':'[', '}':'{'} + stack := make([]byte, 0) + if s == "" { + return true + } + for i := 0; i < len(s); i++ { + if s[i] == '(' || s[i] == '[' || s[i] == '{' { + stack = append(stack, s[i]) + } else if len(stack) > 0 && stack[len(stack)-1] == hash[s[i]] { + stack = stack[:len(stack)-1] + } else { + return false + } + } + return len(stack) == 0 +} +``` From 31872280c9107a2544c11e30aed58e7bf6cc89f8 Mon Sep 17 00:00:00 2001 From: Chengkq <1395092352@qq.com> Date: Thu, 13 May 2021 14:29:08 +0800 Subject: [PATCH 36/36] =?UTF-8?q?update=200404=20=E5=B7=A6=E5=8F=B6?= =?UTF-8?q?=E5=AD=90=E4=B9=8B=E5=92=8C?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0101.对称二叉树.md | 5 ----- problems/0110.平衡二叉树.md | 5 ----- 2 files changed, 10 deletions(-) diff --git a/problems/0101.对称二叉树.md b/problems/0101.对称二叉树.md index b9e203e8..535300af 100644 --- a/problems/0101.对称二叉树.md +++ b/problems/0101.对称二叉树.md @@ -255,11 +255,6 @@ public: Java： -```java -``` - - - Python： diff --git a/problems/0110.平衡二叉树.md b/problems/0110.平衡二叉树.md index ee215a68..3807aecc 100644 --- a/problems/0110.平衡二叉树.md +++ b/problems/0110.平衡二叉树.md @@ -355,11 +355,6 @@ public: Java： -```java -``` - - - Python：