From d1d3b28341c6f13ca0cc9ee2fd66f5f82af9575c Mon Sep 17 00:00:00 2001 From: Guanzhong Pan Date: Mon, 29 Nov 2021 11:56:50 +0000 Subject: [PATCH 01/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200015.=E4=B8=89?= =?UTF-8?q?=E6=95=B0=E4=B9=8B=E5=92=8C.md=20C=E8=AF=AD=E8=A8=80=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/0015.三数之和.md | 74 +++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/problems/0015.三数之和.md b/problems/0015.三数之和.md index dec8a7c6..1e675254 100644 --- a/problems/0015.三数之和.md +++ b/problems/0015.三数之和.md @@ -435,5 +435,79 @@ func threeSum(_ nums: [Int]) -> [[Int]] { } ``` +C: +```C +//qsort辅助cmp函数 +int cmp(const void* ptr1, const void* ptr2) { + return *((int*)ptr1) > *((int*)ptr2); +} + +int** threeSum(int* nums, int numsSize, int* returnSize, int** returnColumnSizes) { + //开辟ans数组空间 + int **ans = (int**)malloc(sizeof(int*) * 18000); + int ansTop = 0; + //若传入nums数组大小小于3，则需要返回数组大小为0 + if(numsSize < 3) { + *returnSize = 0; + return ans; + } + //对nums数组进行排序 + qsort(nums, numsSize, sizeof(int), cmp); + + + int i; + //用for循环遍历数组，结束条件为i < numsSize - 2(因为要预留左右指针的位置) + for(i = 0; i < numsSize - 2; i++) { + //若当前i指向元素>0，则代表left和right以及i的和大于0。直接break + if(nums[i] > 0) + break; + //去重：i > 0 && nums[i] == nums[i-1] + if(i > 0 && nums[i] == nums[i-1]) + continue; + //定义左指针和右指针 + int left = i + 1; + int right = numsSize - 1; + //当右指针比左指针大时进行循环 + while(right > left) { + //求出三数之和 + int sum = nums[right] + nums[left] + nums[i]; + //若和小于0，则左指针+1（因为左指针右边的数比当前所指元素大） + if(sum < 0) + left++; + //若和大于0，则将右指针-1 + else if(sum > 0) + right--; + //若和等于0 + else { + //开辟一个大小为3的数组空间，存入nums[i], nums[left]和nums[right] + int* arr = (int*)malloc(sizeof(int) * 3); + arr[0] = nums[i]; + arr[1] = nums[left]; + arr[2] = nums[right]; + //将开辟数组存入ans中 + ans[ansTop++] = arr; + //去重 + while(right > left && nums[right] == nums[right - 1]) + right--; + while(left < right && nums[left] == nums[left + 1]) + left++; + //更新左右指针 + left++; + right--; + } + } + } + + //设定返回的数组大小 + *returnSize = ansTop; + *returnColumnSizes = (int*)malloc(sizeof(int) * ansTop); + int z; + for(z = 0; z < ansTop; z++) { + (*returnColumnSizes)[z] = 3; + } + return ans; +} +``` + -----------------------
From 77b31bb0caaca95080c29844098f6bbb0e7f75b1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=9E=81=E5=AE=A2=E5=AD=A6=E4=BC=9F?= Date: Tue, 30 Nov 2021 14:07:32 +0800 Subject: [PATCH 02/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20150.=20=E9=80=86?= =?UTF-8?q?=E6=B3=A2=E5=85=B0=E8=A1=A8=E8=BE=BE=E5=BC=8F=E6=B1=82=E5=80=BC?= =?UTF-8?q?=20Swift=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0150.逆波兰表达式求值.md | 32 +++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/problems/0150.逆波兰表达式求值.md b/problems/0150.逆波兰表达式求值.md index ef91330d..137aaf5d 100644 --- a/problems/0150.逆波兰表达式求值.md +++ b/problems/0150.逆波兰表达式求值.md @@ -241,6 +241,38 @@ class Solution: ``` +Swift： +```Swift +func evalRPN(_ tokens: [String]) -> Int { + var stack = [Int]() + for c in tokens { + let v = Int(c) + if let num = v { + // 遇到数字直接入栈 + stack.append(num) + } else { + // 遇到运算符, 取出栈顶两元素计算, 结果压栈 + var res: Int = 0 + let num2 = stack.popLast()! + let num1 = stack.popLast()! + switch c { + case "+": + res = num1 + num2 + case "-": + res = num1 - num2 + case "*": + res = num1 * num2 + case "/": + res = num1 / num2 + default: + break + } + stack.append(res) + } + } + return stack.last! +} +``` -----------------------
From 4dfa4d1ae2c3be414c51d0e1fb056567d2e2d938 Mon Sep 17 00:00:00 2001 From: Luo <82520819+Jerry-306@users.noreply.github.com> Date: Wed, 1 Dec 2021 19:43:05 +0800 Subject: [PATCH 03/13] =?UTF-8?q?=E7=AE=97=E6=B3=95=E6=A8=A1=E6=9D=BF=20js?= =?UTF-8?q?=20=E7=89=88=E6=9C=AC=E4=BB=A3=E7=A0=81=E6=A0=B7=E5=BC=8F?= =?UTF-8?q?=E5=BE=AE=E8=B0=83?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/算法模板.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/problems/算法模板.md b/problems/算法模板.md index 853816d2..69ebb361 100644 --- a/problems/算法模板.md +++ b/problems/算法模板.md @@ -460,7 +460,7 @@ var levelOrder = function (root) { for (let i = 0; i < n; i++) { let node = queue.shift(); temp.push(node.val); - node.left &&queue.push(node.left); + node.left && queue.push(node.left); node.right && queue.push(node.right); } res.push(temp); From 0ab6e244f9df46186d8737c583e8bf1f3cc1b72f Mon Sep 17 00:00:00 2001 From: Luo <82520819+Jerry-306@users.noreply.github.com> Date: Wed, 1 Dec 2021 19:54:06 +0800 Subject: [PATCH 04/13] =?UTF-8?q?=E4=BF=AE=E5=A4=8D=200704=20=E4=BA=8C?= =?UTF-8?q?=E5=88=86=E6=9F=A5=E6=89=BE=20js=E7=89=88=E6=9C=AC=E4=BB=A3?= =?UTF-8?q?=E7=A0=81=E6=97=A0=E9=AB=98=E4=BA=AE=E6=A0=B7=E5=BC=8F=E9=97=AE?= =?UTF-8?q?=E9=A2=98?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0704.二分查找.md | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/problems/0704.二分查找.md b/problems/0704.二分查找.md index bb10143f..44a0c1d8 100644 --- a/problems/0704.二分查找.md +++ b/problems/0704.二分查找.md @@ -276,11 +276,9 @@ func search(nums []int, target int) int { ``` **JavaScript:** +（版本一）左闭右闭区间 ```js - -// （版本一）左闭右闭区间 - /** * @param {number[]} nums * @param {number} target @@ -302,9 +300,10 @@ var search = function(nums, target) { } return -1; }; +``` +（版本二）左闭右开区间 -// （版本二）左闭右开区间 - +```js /** * @param {number[]} nums * @param {number} target @@ -325,7 +324,6 @@ var search = function(nums, target) { } return -1; }; - ``` **Ruby:** From 44a3e351f09b4f02ba57b19fcb33c3e4cb3d07e9 Mon Sep 17 00:00:00 2001 From: Luo <82520819+Jerry-306@users.noreply.github.com> Date: Wed, 1 Dec 2021 20:10:33 +0800 Subject: [PATCH 05/13] =?UTF-8?q?=E6=96=B0=E5=A2=9E=200977=20=E6=9C=89?= =?UTF-8?q?=E5=BA=8F=E6=95=B0=E7=BB=84=E7=9A=84=E5=B9=B3=E6=96=B9=20JavaSc?= =?UTF-8?q?ript=E7=89=88=E6=9C=AC=20=E6=9B=B4=E5=8A=A0=E7=AE=80=E6=B4=81?= =?UTF-8?q?=E9=AB=98=E6=95=88=E7=9A=84=E8=A7=A3=E6=B3=95?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0977.有序数组的平方.md | 37 +++++++++++++------------- 1 file changed, 18 insertions(+), 19 deletions(-) diff --git a/problems/0977.有序数组的平方.md b/problems/0977.有序数组的平方.md index b1e04c4e..6616ba8c 100644 --- a/problems/0977.有序数组的平方.md +++ b/problems/0977.有序数组的平方.md @@ -199,27 +199,26 @@ impl Solution { Javascript： ```Javascript /** - * @desc two pointers solution - * @link https://leetcode-cn.com/problems/squares-of-a-sorted-array/ - * @param nums Array e.g. [-4,-1,0,3,10] - * @return {array} e.g. [0,1,9,16,100] + * @param {number[]} nums + * @return {number[]} */ -const sortedSquares = function (nums) { - let res = [] - for (let i = 0, j = nums.length - 1; i <= j;) { - const left = Math.abs(nums[i]) - const right = Math.abs(nums[j]) - if (right > left) { - // push element to the front of the array - res.unshift(right * right) - j-- - } else { - res.unshift(left * left) - i++ - } +var sortedSquares = function(nums) { + let n = nums.length; + let res = new Array(n).fill(0); + let i = 0, j = n - 1, k = n - 1; + while (i <= j) { + let left = nums[i] * nums[i], + right = nums[j] * nums[j]; + if (left < right) { + res[k--] = right; + j--; + } else { + res[k--] = left; + i++; + } } - return res - } + return res; +}; ``` Swift: From 2789554d525d2e02d94b669bdf582441bd249d19 Mon Sep 17 00:00:00 2001 From: Luo <82520819+Jerry-306@users.noreply.github.com> Date: Wed, 1 Dec 2021 20:56:22 +0800 Subject: [PATCH 06/13] =?UTF-8?q?=E6=9B=B4=E6=AD=A3=200019=20=E5=88=A0?= =?UTF-8?q?=E9=99=A4=E9=93=BE=E8=A1=A8=E4=B8=AD=E5=80=92=E6=95=B0=E7=AC=AC?= =?UTF-8?q?N=E4=B8=AA=E8=8A=82=E7=82=B9=20JavaScript=20=E4=BB=A3=E7=A0=81?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0019.删除链表的倒数第N个节点.md | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) 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 e05b9d03..188c4c57 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 @@ -173,8 +173,7 @@ var removeNthFromEnd = function(head, n) { let ret = new ListNode(0, head), slow = fast = ret; while(n--) fast = fast.next; - if(!fast) return ret.next; - while (fast.next) { + while (fast.next !== null) { fast = fast.next; slow = slow.next }; From 9483a652ee511371cbfe405425417a7c9f1d2583 Mon Sep 17 00:00:00 2001 From: Asterisk <44215173+casnz1601@users.noreply.github.com> Date: Sun, 5 Dec 2021 16:43:47 +0800 Subject: [PATCH 07/13] =?UTF-8?q?Update=200205.=E5=90=8C=E6=9E=84=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/0205.同构字符串.md | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/problems/0205.同构字符串.md b/problems/0205.同构字符串.md index a2963149..eeda7d2e 100644 --- a/problems/0205.同构字符串.md +++ b/problems/0205.同构字符串.md @@ -90,6 +90,24 @@ class Solution { ## Python ```python +class Solution: + def isIsomorphic(self, s: str, t: str) -> bool: + default_dict1 = defaultdict(str) + default_dict2 = defaultdict(str) + + if len(s) != len(t): return false + + for i in range(len(s)): + if not default_dict1[s[i]]: + default_dict1[s[i]] = t[i] + + if not default_dict2[t[i]]: + default_dict2[t[i]] = s[i] + + if default_dict1[s[i]] != t[i] or default_dict2[t[i]] != s[i]: + return False + + return True ``` ## Go From 3ae922f6f17a3d7ccc9a6f713572a4a96bfba4e5 Mon Sep 17 00:00:00 2001 From: mx lai <1721261216@qq.com> Date: Sun, 5 Dec 2021 19:56:17 +0800 Subject: [PATCH 08/13] =?UTF-8?q?FIX:=20=E6=9B=B4=E6=AD=A30098.=E9=AA=8C?= =?UTF-8?q?=E8=AF=81=E4=BA=8C=E5=8F=89=E6=90=9C=E7=B4=A2=E6=A0=91go?= =?UTF-8?q?=E8=AF=AD=E8=A8=80=E7=89=88=E7=9A=84=E4=BB=A3=E7=A0=81?= 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 | 29 +++++++++++++++----------- 1 file changed, 17 insertions(+), 12 deletions(-) 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 ec265615..82d1941e 100644 --- a/problems/0098.验证二叉搜索树.md +++ b/problems/0098.验证二叉搜索树.md @@ -414,19 +414,24 @@ class Solution: import "math" func isValidBST(root *TreeNode) bool { - if root == nil { - return true - } - return isBST(root, math.MinInt64, math.MaxFloat64) + // 二叉搜索树也可以是空树 + if root == nil { + return true + } + // 由题目中的数据限制可以得出min和max + return check(root,math.MinInt64,math.MaxInt64) } -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) + +func check(node *TreeNode,min,max int64) bool { + if node == nil { + return true + } + + if min >= int64(node.Val) || max <= int64(node.Val) { + return false + } + // 分别对左子树和右子树递归判断，如果左子树和右子树都符合则返回true + return check(node.Right,int64(node.Val),max) && check(node.Left,min,int64(node.Val)) } ``` ```go From 6b5049883b99aeed7179146d732c3863c5e70283 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=9E=81=E5=AE=A2=E5=AD=A6=E4=BC=9F?= Date: Tue, 7 Dec 2021 14:47:48 +0800 Subject: [PATCH 09/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20239.=20=E6=BB=91?= =?UTF-8?q?=E5=8A=A8=E7=AA=97=E5=8F=A3=E6=9C=80=E5=A4=A7=E5=80=BC=20Swift?= =?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/0239.滑动窗口最大值.md | 106 +++++++++++++++++++++++++ 1 file changed, 106 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 8a8d3a52..1f245699 100644 --- a/problems/0239.滑动窗口最大值.md +++ b/problems/0239.滑动窗口最大值.md @@ -418,6 +418,112 @@ var maxSlidingWindow = function (nums, k) { }; ``` +Swift: +```Swift +/// 双向链表 +class DoublyListNode { + var head: DoublyListNode? + var tail: DoublyListNode? + var next: DoublyListNode? + var pre: DoublyListNode? + var value: Int = 0 + init(_ value: Int = 0) { + self.value = value + } + func isEmpty() -> Bool { + return self.head == nil + } + func first() -> Int? { + return self.head?.value + } + func last() -> Int? { + return self.tail?.value + } + func removeFirst() { + if isEmpty() { + return + } + let next = self.head!.next + self.head?.next = nil// 移除首节点 + next?.pre = nil + self.head = next + } + func removeLast() { + if let tail = self.tail { + if let pre = tail.pre { + self.tail?.pre = nil + pre.next = nil + self.tail = pre + } else { + self.head = nil + self.tail = nil + } + } + } + func append(_ value: Int) { + let node = DoublyListNode(value) + if self.head != nil { + node.pre = self.tail + self.tail?.next = node + self.tail = node + } else { + self.head = node + self.tail = node + self.pre = nil + self.next = nil + } + } +} +// 单调队列, 从大到小 +class MyQueue { +// var queue: [Int]!// 用数组会超时 + var queue: DoublyListNode! + init() { +// queue = [Int]() + queue = DoublyListNode() + } + // 滑动窗口时弹出第一个元素, 如果相等再弹出 + func pop(x: Int) { + if !queue.isEmpty() && front() == x { + queue.removeFirst() + } + } + // 滑动窗口时添加下一个元素, 移除队尾比 x 小的元素 始终保证队头 > 队尾 + func push(x: Int) { + while !queue.isEmpty() && queue.last()! < x { + queue.removeLast() + } + queue.append(x) + } + // 此时队头就是滑动窗口最大值 + func front() -> Int { + return queue.first() ?? -1 + } +} + +class Solution { + func maxSlidingWindow(_ nums: [Int], _ k: Int) -> [Int] { + // 存放结果 + var res = [Int]() + let queue = MyQueue() + // 先将前K个元素放入队列 + for i in 0 ..< k { + queue.push(x: nums[i]) + } + // 添加当前队列最大值到结果数组 + res.append(queue.front()) + for i in k ..< nums.count { + // 滑动窗口移除最前面元素 + queue.pop(x: nums[i - k]) + // 滑动窗口添加下一个元素 + queue.push(x: nums[i]) + // 保存当前队列最大值 + res.append(queue.front()) + } + return res + } +} +``` -----------------------
From 0d442b3b7bdde1dd81576778efaeb758946c8f6c Mon Sep 17 00:00:00 2001 From: mengyuan Date: Tue, 7 Dec 2021 21:42:05 +0800 Subject: [PATCH 10/13] =?UTF-8?q?update:=200040.=E7=BB=84=E5=90=88?= =?UTF-8?q?=E6=80=BB=E5=92=8CII=20JS=E7=89=88=E6=9C=AC=E5=A2=9E=E5=8A=A0?= =?UTF-8?q?=E4=BD=BF=E7=94=A8used=E5=8E=BB=E9=87=8D?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0040.组合总和II.md | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/problems/0040.组合总和II.md b/problems/0040.组合总和II.md index bab4bd6a..b5e511e7 100644 --- a/problems/0040.组合总和II.md +++ b/problems/0040.组合总和II.md @@ -457,6 +457,37 @@ var combinationSum2 = function(candidates, target) { } }; ``` +**使用used去重** +```js +var combinationSum2 = function(candidates, target) { + let res = []; + let path = []; + let total = 0; + const len = candidates.length; + candidates.sort((a, b) => a - b); + let used = new Array(len).fill(false); + const backtracking = (startIndex) => { + if (total === target) { + res.push([...path]); + return; + } + for(let i = startIndex; i < len && total < target; i++) { + const cur = candidates[i]; + if (cur > target - total || (i > 0 && cur === candidates[i - 1] && !used[i - 1])) continue; + path.push(cur); + total += cur; + used[i] = true; + backtracking(i + 1); + path.pop(); + total -= cur; + used[i] = false; + } + } + backtracking(0); + return res; +}; +``` + ## C ```c From 27bb2b0485edcea24bb54cbf4834a972b1200248 Mon Sep 17 00:00:00 2001 From: topsy404 <87177008+topsy404@users.noreply.github.com> Date: Wed, 8 Dec 2021 14:28:34 +0800 Subject: [PATCH 11/13] fix typo --- problems/0416.分割等和子集.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/problems/0416.分割等和子集.md b/problems/0416.分割等和子集.md index b661a766..393baf7d 100644 --- a/problems/0416.分割等和子集.md +++ b/problems/0416.分割等和子集.md @@ -68,7 +68,7 @@ * 背包的体积为sum / 2 * 背包要放入的商品（集合里的元素）重量为 元素的数值，价值也为元素的数值 -* 背包如何正好装满，说明找到了总和为 sum / 2 的子集。 +* 背包如果正好装满，说明找到了总和为 sum / 2 的子集。 * 背包中每一个元素是不可重复放入。 以上分析完，我们就可以套用01背包，来解决这个问题了。 From c5b691b91dc85cc16304fb9884d9db4afadb88e0 Mon Sep 17 00:00:00 2001 From: zhicheng lee <904688436@qq.com> Date: Wed, 8 Dec 2021 16:49:06 +0800 Subject: [PATCH 12/13] =?UTF-8?q?Update=200236.=E4=BA=8C=E5=8F=89=E6=A0=91?= =?UTF-8?q?=E7=9A=84=E6=9C=80=E8=BF=91=E5=85=AC=E5=85=B1=E7=A5=96=E5=85=88?= =?UTF-8?q?.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 更新 0236题 Java版本代码 --- .../0236.二叉树的最近公共祖先.md | 40 +++++++------------ 1 file changed, 14 insertions(+), 26 deletions(-) diff --git a/problems/0236.二叉树的最近公共祖先.md b/problems/0236.二叉树的最近公共祖先.md index 4182999f..6d26e376 100644 --- a/problems/0236.二叉树的最近公共祖先.md +++ b/problems/0236.二叉树的最近公共祖先.md @@ -221,42 +221,30 @@ public: ## Java + ```Java class Solution { public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) { - return lowestCommonAncestor1(root, p, q); - } - public TreeNode lowestCommonAncestor1(TreeNode root, TreeNode p, TreeNode q) { - if (root == null || root == p || root == q) { + if (root == null || root == p || root == q) { // 递归结束条件 return root; } - TreeNode left = lowestCommonAncestor1(root.left, p, q); - TreeNode right = lowestCommonAncestor1(root.right, p, q); - if (left != null && right != null) {// 左右子树分别找到了，说明此时的root就是要求的结果 - return root; - } - if (left == null) { + + // 后序遍历 + TreeNode left = lowestCommonAncestor(root.left, p, q); + TreeNode right = lowestCommonAncestor(root.right, p, q); + + if(left == null && right == null) { // 若未找到节点 p 或 q + return null; + }else if(left == null && right != null) { // 若找到一个节点 return right; + }else if(left != null && right == null) { // 若找到一个节点 + return left; + }else { // 若找到两个节点 + return root; } - return left; } } -``` - -```java -// 代码精简版 -class Solution { - public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) { - if (root == null || root.val == p.val ||root.val == q.val) return root; - TreeNode left = lowestCommonAncestor(root.left,p,q); - TreeNode right = lowestCommonAncestor(root.right,p,q); - if (left != null && right != null) return root; - else if (left == null && right != null) return right; - else if (left != null && right == null) return left; - else return null; - } -} ``` ## Python From 38b8b343c931019e76d7692b99ee7d397538494c Mon Sep 17 00:00:00 2001 From: zhicheng lee <904688436@qq.com> Date: Thu, 9 Dec 2021 11:16:22 +0800 Subject: [PATCH 13/13] =?UTF-8?q?=E6=9B=B4=E6=96=B0=20=E9=A2=98=E7=9B=AE07?= =?UTF-8?q?01=20Java=E7=89=88=E6=9C=AC=E4=BB=A3=E7=A0=81?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0701.二叉搜索树中的插入操作.md | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/problems/0701.二叉搜索树中的插入操作.md b/problems/0701.二叉搜索树中的插入操作.md index 5d63ce58..1e6ab47e 100644 --- a/problems/0701.二叉搜索树中的插入操作.md +++ b/problems/0701.二叉搜索树中的插入操作.md @@ -236,16 +236,13 @@ class Solution { ```java class Solution { public TreeNode insertIntoBST(TreeNode root, int val) { - return buildTree(root, val); - } - - public TreeNode buildTree(TreeNode root, int val){ if (root == null) // 如果当前节点为空，也就意味着val找到了合适的位置，此时创建节点直接返回。 return new TreeNode(val); + if (root.val < val){ - root.right = buildTree(root.right, val); // 递归创建右子树 + root.right = insertIntoBST(root.right, val); // 递归创建右子树 }else if (root.val > val){ - root.left = buildTree(root.left, val); // 递归创建左子树 + root.left = insertIntoBST(root.left, val); // 递归创建左子树 } return root; }