diff --git a/README.md b/README.md index 5121dd29..c5149776 100644 --- a/README.md +++ b/README.md @@ -4,9 +4,9 @@ 👉 推荐 [Gitee同步](https://gitee.com/programmercarl/leetcode-master) > 1. **介绍**:本项目是一套完整的刷题计划,旨在帮助大家少走弯路,循序渐进学算法,[关注作者](#关于作者) -> 2. **PDF版本** : [「代码随想录」算法精讲 PDF 版本](https://mp.weixin.qq.com/s/NF7NqTD9DU505S6nvR_5Wg) 。 +> 2. **PDF版本** : [「代码随想录」算法精讲 PDF 版本](https://programmercarl.com/other/algo_pdf.html) 。 > 3. **刷题顺序** : README已经将刷题顺序排好了,按照顺序一道一道刷就可以。 -> 4. **学习社区** : 一起学习打卡/面试技巧/如何选择offer/大厂内推/职场规则/简历修改/技术分享/程序人生。欢迎加入[「代码随想录」知识星球](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) 。 +> 4. **学习社区** : 一起学习打卡/面试技巧/如何选择offer/大厂内推/职场规则/简历修改/技术分享/程序人生。欢迎加入[「代码随想录」知识星球](https://programmercarl.com/other/kstar.html) 。 > 5. **提交代码**:本项目统一使用C++语言进行讲解,但已经有Java、Python、Go、JavaScript等等多语言版本,感谢[这里的每一位贡献者](https://github.com/youngyangyang04/leetcode-master/graphs/contributors),如果你也想贡献代码点亮你的头像,[点击这里](https://mp.weixin.qq.com/s/tqCxrMEU-ajQumL1i8im9A)了解提交代码的方式。 > 6. **转载须知** :以下所有文章皆为我([程序员Carl](https://github.com/youngyangyang04))的原创。引用本项目文章请注明出处,发现恶意抄袭或搬运,会动用法律武器维护自己的权益。让我们一起维护一个良好的技术创作环境! @@ -564,14 +564,14 @@ # 关于作者 -大家好,我是程序员Carl,哈工大师兄,ACM 校赛、黑龙江省赛、东北四省赛金牌、亚洲区域赛铜牌获得者,先后在腾讯和百度从事后端技术研发,CSDN博客专家。对算法和C++后端技术有一定的见解,利用工作之余重新刷leetcode。 +大家好,我是程序员Carl,哈工大师兄,《代码随想录》作者,先后在腾讯和百度从事后端技术研发,CSDN博客专家。对算法和C++后端技术有一定的见解,利用工作之余重新刷leetcode。 -加入刷题微信群,备注:「个人简单介绍」 + 组队刷题 +加入「代码随想录」刷题小分队(微信群),可以扫下方二维码加我微信。 -也欢迎与我交流,备注:「个人简单介绍」 + 交流,围观朋友圈,做点赞之交(备注没有自我介绍不通过哦) +如果是已工作,备注:姓名-城市-岗位-组队刷题。如果学生,备注:姓名-学校-年级-组队刷题。**备注没有自我介绍不通过哦** + +
- -
# 公众号 @@ -585,10 +585,3 @@
-# 服务器 - -

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-

- - - diff --git a/problems/0027.移除元素.md b/problems/0027.移除元素.md index 693684f3..99990302 100644 --- a/problems/0027.移除元素.md +++ b/problems/0027.移除元素.md @@ -197,7 +197,23 @@ var removeElement = (nums, val) => { }; ``` +TypeScript: + +```typescript +function removeElement(nums: number[], val: number): number { + let slowIndex: number = 0, fastIndex: number = 0; + while (fastIndex < nums.length) { + if (nums[fastIndex] !== val) { + nums[slowIndex++] = nums[fastIndex]; + } + fastIndex++; + } + return slowIndex; +}; +``` + Ruby: + ```ruby def remove_element(nums, val) i = 0 diff --git a/problems/0028.实现strStr.md b/problems/0028.实现strStr.md index ef7008bc..f0b56719 100644 --- a/problems/0028.实现strStr.md +++ b/problems/0028.实现strStr.md @@ -649,6 +649,41 @@ class Solution { } ``` +```Java +class Solution { + //前缀表(不减一)Java实现 + public int strStr(String haystack, String needle) { + if (needle.length() == 0) return 0; + int[] next = new int[needle.length()]; + getNext(next, needle); + + int j = 0; + for (int i = 0; i < haystack.length(); i++) { + while (j > 0 && needle.charAt(j) != haystack.charAt(i)) + j = next[j - 1]; + if (needle.charAt(j) == haystack.charAt(i)) + j++; + if (j == needle.length()) + return i - needle.length() + 1; + } + return -1; + + } + + private void getNext(int[] next, String s) { + int j = 0; + next[0] = 0; + for (int i = 1; i < s.length(); i++) { + while (j > 0 && s.charAt(j) != s.charAt(i)) + j = next[j - 1]; + if (s.charAt(j) == s.charAt(i)) + j++; + next[i] = j; + } + } +} +``` + Python3: ```python diff --git a/problems/0040.组合总和II.md b/problems/0040.组合总和II.md index 14737e31..54384188 100644 --- a/problems/0040.组合总和II.md +++ b/problems/0040.组合总和II.md @@ -255,6 +255,7 @@ public: ## Java +**使用标记数组** ```Java class Solution { List> lists = new ArrayList<>(); @@ -292,6 +293,44 @@ class Solution { } } ``` +**不使用标记数组** +```Java +class Solution { + List> res = new ArrayList<>(); + LinkedList path = new LinkedList<>(); + int sum = 0; + + public List> combinationSum2( int[] candidates, int target ) { + //为了将重复的数字都放到一起,所以先进行排序 + Arrays.sort( candidates ); + backTracking( candidates, target, 0 ); + return res; + } + + private void backTracking( int[] candidates, int target, int start ) { + if ( sum == target ) { + res.add( new ArrayList<>( path ) ); + return; + } + for ( int i = start; i < candidates.length && sum + candidates[i] <= target; i++ ) { + //正确剔除重复解的办法 + //跳过同一树层使用过的元素 + if ( i > start && candidates[i] == candidates[i - 1] ) { + continue; + } + + sum += candidates[i]; + path.add( candidates[i] ); + // i+1 代表当前组内元素只选取一次 + backTracking( candidates, target, i + 1 ); + + int temp = path.getLast(); + sum -= temp; + path.removeLast(); + } + } +} +``` ## Python **回溯+巧妙去重(省去使用used** @@ -384,6 +423,7 @@ class Solution: ## Go 主要在于如何在回溯中去重 +**使用used数组** ```go func combinationSum2(candidates []int, target int) [][]int { var trcak []int @@ -423,7 +463,41 @@ func backtracking(startIndex,sum,target int,candidates,trcak []int,res *[][]int, } } ``` - +**不使用used数组** +```go +func combinationSum2(candidates []int, target int) [][]int { + var trcak []int + var res [][]int + sort.Ints(candidates) + backtracking(0,0,target,candidates,trcak,&res) + return res +} +func backtracking(startIndex,sum,target int,candidates,trcak []int,res *[][]int){ + //终止条件 + if sum==target{ + tmp:=make([]int,len(trcak)) + //拷贝 + copy(tmp,trcak) + //放入结果集 + *res=append(*res,tmp) + return + } + //回溯 + for i:=startIndex;istartIndex&&candidates[i]==candidates[i-1]{ + continue + } + //更新路径集合和sum + trcak=append(trcak,candidates[i]) + sum+=candidates[i] + backtracking(i+1,sum,target,candidates,trcak,res) + //回溯 + trcak=trcak[:len(trcak)-1] + sum-=candidates[i] + } +} +``` ## javaScript ```js diff --git a/problems/0077.组合.md b/problems/0077.组合.md index 8e944eb3..2bd7a287 100644 --- a/problems/0077.组合.md +++ b/problems/0077.组合.md @@ -422,13 +422,13 @@ class Solution: def backtrack(n,k,startIndex): if len(path) == k: res.append(path[:]) - return + return for i in range(startIndex,n - (k - len(path)) + 2): #优化的地方 path.append(i) #处理节点 backtrack(n,k,i+1) #递归 path.pop() #回溯,撤销处理的节点 - backtrack(n,k,1) - return res + backtrack(n,k,1) + return res ``` diff --git a/problems/0077.组合优化.md b/problems/0077.组合优化.md index bd941e03..e995fd18 100644 --- a/problems/0077.组合优化.md +++ b/problems/0077.组合优化.md @@ -182,13 +182,13 @@ class Solution: def backtrack(n,k,startIndex): if len(path) == k: res.append(path[:]) - return + return for i in range(startIndex,n-(k-len(path))+2): #优化的地方 path.append(i) #处理节点 backtrack(n,k,i+1) #递归 path.pop() #回溯,撤销处理的节点 - backtrack(n,k,1) - return res + backtrack(n,k,1) + return res ``` Go: ```Go diff --git a/problems/0090.子集II.md b/problems/0090.子集II.md index 1ae5c966..16bd1f2c 100644 --- a/problems/0090.子集II.md +++ b/problems/0090.子集II.md @@ -166,7 +166,7 @@ if (i > startIndex && nums[i] == nums[i - 1] ) { ### Java - +使用used数组 ```java class Solution { List> result = new ArrayList<>();// 存放符合条件结果的集合 @@ -202,6 +202,37 @@ class Solution { } ``` +不使用used数组 +```java +class Solution { + + List> res = new ArrayList<>(); + LinkedList path = new LinkedList<>(); + + public List> subsetsWithDup( int[] nums ) { + Arrays.sort( nums ); + subsetsWithDupHelper( nums, 0 ); + return res; + } + + + private void subsetsWithDupHelper( int[] nums, int start ) { + res.add( new ArrayList<>( path ) ); + + for ( int i = start; i < nums.length; i++ ) { + // 跳过当前树层使用过的、相同的元素 + if ( i > start && nums[i - 1] == nums[i] ) { + continue; + } + path.add( nums[i] ); + subsetsWithDupHelper( nums, i + 1 ); + path.removeLast(); + } + } + +} +``` + ### Python ```python class Solution: diff --git a/problems/0209.长度最小的子数组.md b/problems/0209.长度最小的子数组.md index 80822436..17422ca0 100644 --- a/problems/0209.长度最小的子数组.md +++ b/problems/0209.长度最小的子数组.md @@ -107,7 +107,7 @@ public: }; ``` -时间复杂度:$O(n)$ +时间复杂度:$O(n)$ 空间复杂度:$O(1)$ **一些录友会疑惑为什么时间复杂度是$O(n)$**。 @@ -121,7 +121,6 @@ public: - ## 其他语言版本 @@ -214,6 +213,28 @@ var minSubArrayLen = function(target, nums) { }; ``` +Typescript: + +```typescript +function minSubArrayLen(target: number, nums: number[]): number { + let left: number = 0, right: number = 0; + let res: number = nums.length + 1; + let sum: number = 0; + while (right < nums.length) { + sum += nums[right]; + if (sum >= target) { + // 不断移动左指针,直到不能再缩小为止 + while (sum - nums[left] >= target) { + sum -= nums[left++]; + } + res = Math.min(res, right - left + 1); + } + right++; + } + return res === nums.length + 1 ? 0 : res; +}; +``` + Swift: ```swift @@ -291,5 +312,23 @@ class Solution { } ``` +Ruby: + +```ruby +def min_sub_array_len(target, nums) + res = Float::INFINITY # 无穷大 + i, sum = 0, 0 + nums.length.times do |j| + sum += nums[j] + while sum >= target + res = [res, j - i + 1].min + sum -= nums[i] + i += 1 + end + end + res == Float::INFINITY ? 0 : res +end +``` + -----------------------

diff --git a/problems/0216.组合总和III.md b/problems/0216.组合总和III.md index 26c630b9..0bb42192 100644 --- a/problems/0216.组合总和III.md +++ b/problems/0216.组合总和III.md @@ -323,7 +323,6 @@ class Solution: self.backtracking(k, n, i + 1) self.path.pop() self.sum_now -= i - return ``` ## Go diff --git a/problems/0222.完全二叉树的节点个数.md b/problems/0222.完全二叉树的节点个数.md index c5039039..754a6094 100644 --- a/problems/0222.完全二叉树的节点个数.md +++ b/problems/0222.完全二叉树的节点个数.md @@ -80,7 +80,7 @@ return treeNum; class Solution { private: int getNodesNum(TreeNode* cur) { - if (cur == 0) return 0; + if (cur == NULL) return 0; int leftNum = getNodesNum(cur->left); // 左 int rightNum = getNodesNum(cur->right); // 右 int treeNum = leftNum + rightNum + 1; // 中 diff --git a/problems/0309.最佳买卖股票时机含冷冻期.md b/problems/0309.最佳买卖股票时机含冷冻期.md index 18c940d4..2dc1e874 100644 --- a/problems/0309.最佳买卖股票时机含冷冻期.md +++ b/problems/0309.最佳买卖股票时机含冷冻期.md @@ -93,7 +93,7 @@ dp[i][3] = dp[i - 1][2]; 综上分析,递推代码如下: ```CPP -dp[i][0] = max(dp[i - 1][0], max(dp[i - 1][3], dp[i - 1][1]) - prices[i]; +dp[i][0] = max(dp[i - 1][0], max(dp[i - 1][3], dp[i - 1][1]) - prices[i]); dp[i][1] = max(dp[i - 1][1], dp[i - 1][3]); dp[i][2] = dp[i - 1][0] + prices[i]; dp[i][3] = dp[i - 1][2]; diff --git a/problems/0704.二分查找.md b/problems/0704.二分查找.md index 689c0633..379cb5fc 100644 --- a/problems/0704.二分查找.md +++ b/problems/0704.二分查找.md @@ -284,7 +284,6 @@ func search(nums []int, target int) int { * @param {number} target * @return {number} */ -/** var search = function(nums, target) { let left = 0, right = nums.length - 1; // 使用左闭右闭区间 @@ -326,6 +325,46 @@ var search = function(nums, target) { }; ``` +**TypeScript** + +(版本一)左闭右闭区间 + +```typescript +function search(nums: number[], target: number): number { + let left: number = 0, right: number = nums.length - 1; + while (left <= right) { + let mid: number = left + Math.floor((right - left) / 2); + if (nums[mid] > target) { + right = mid - 1; + } else if (nums[mid] < target) { + left = mid + 1; + } else { + return mid; + } + } + return -1; +}; +``` + +(版本二)左闭右开区间 + +```typescript +function search(nums: number[], target: number): number { + let left: number = 0, right: number = nums.length; + while (left < right) { + let mid: number = left + Math.floor((right - left) / 2); + if (nums[mid] > target) { + right = mid; + } else if (nums[mid] < target) { + left = mid + 1; + } else { + return mid; + } + } + return -1; +}; +``` + **Ruby:** ```ruby 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 0085de0b..b11fa7ef 100644 --- a/problems/0977.有序数组的平方.md +++ b/problems/0977.有序数组的平方.md @@ -221,6 +221,35 @@ var sortedSquares = function(nums) { }; ``` +Typescript: + +双指针法: + +```typescript +function sortedSquares(nums: number[]): number[] { + let left: number = 0, right: number = nums.length - 1; + let resArr: number[] = new Array(nums.length); + let resArrIndex: number = resArr.length - 1; + while (left <= right) { + if (Math.abs(nums[left]) < Math.abs(nums[right])) { + resArr[resArrIndex] = nums[right--] ** 2; + } else { + resArr[resArrIndex] = nums[left++] ** 2; + } + resArrIndex--; + } + return resArr; +}; +``` + +骚操作法(暴力思路): + +```typescript +function sortedSquares(nums: number[]): number[] { + return nums.map(i => i * i).sort((a, b) => a - b); +}; +``` + Swift: ```swift