From 60f61199853b5de43994ecf482643a855cafb0ee Mon Sep 17 00:00:00 2001 From: kok-s0s <2694308562@qq.com> Date: Fri, 23 Jul 2021 19:14:29 +0800 Subject: [PATCH 01/11] =?UTF-8?q?=E6=8F=90=E4=BE=9BJavaScript=E7=89=88?= =?UTF-8?q?=E6=9C=AC=E7=9A=84=E3=80=8A=E5=B7=A6=E6=97=8B=E8=BD=AC=E5=AD=97?= =?UTF-8?q?=E7=AC=A6=E4=B8=B2=E3=80=8B?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../剑指Offer58-II.左旋转字符串.md | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/problems/剑指Offer58-II.左旋转字符串.md b/problems/剑指Offer58-II.左旋转字符串.md index 1701086e..1f57b4af 100644 --- a/problems/剑指Offer58-II.左旋转字符串.md +++ b/problems/剑指Offer58-II.左旋转字符串.md @@ -162,7 +162,27 @@ func reverse(b []byte, left, right int){ } ``` +JavaScript版本 +```javascript +/** + * @param {string} s + * @param {number} n + * @return {string} + */ +var reverseLeftWords = function (s, n) { + const reverse = (str, left, right) => { + let strArr = str.split(""); + for (; left < right; left++, right--) { + [strArr[left], strArr[right]] = [strArr[right], strArr[left]]; + } + return strArr.join(""); + } + s = reverse(s, 0, n - 1); + s = reverse(s, n, s.length - 1); + return reverse(s, 0, s.length - 1); +}; +``` From 45e996805b4ce94676abb1d5a2e43098403a6a6c Mon Sep 17 00:00:00 2001 From: SwordsmanYao Date: Tue, 27 Jul 2021 16:44:04 +0800 Subject: [PATCH 02/11] =?UTF-8?q?[=E5=89=91=E6=8C=87Offer58-II.=E5=B7=A6?= =?UTF-8?q?=E6=97=8B=E8=BD=AC=E5=AD=97=E7=AC=A6=E4=B8=B2]=20=E6=B7=BB?= =?UTF-8?q?=E5=8A=A0js=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 --- .../剑指Offer58-II.左旋转字符串.md | 31 +++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/problems/剑指Offer58-II.左旋转字符串.md b/problems/剑指Offer58-II.左旋转字符串.md index 3c3eaef0..8a60252c 100644 --- a/problems/剑指Offer58-II.左旋转字符串.md +++ b/problems/剑指Offer58-II.左旋转字符串.md @@ -165,6 +165,37 @@ func reverse(b []byte, left, right int){ ``` +javaScript: + +```js +/** + * @param {string} s + * @param {number} n + * @return {string} + */ + var reverseLeftWords = function(s, n) { + const strArr = Array.from(s); + reverse(strArr, 0, n - 1); + reverse(strArr, n, strArr.length - 1); + reverse(strArr, 0, strArr.length - 1); + return strArr.join(''); +}; + +// 翻转从 start 到 end 的字符 +function reverse(strArr, start, end) { + let left = start; + let right = end; + + while(left < right) { + // 交换 + [strArr[left], strArr[right]] = [strArr[right], strArr[left]]; + left++; + right--; + } +} +``` + + From 877c8ca4188c59e792e78ee8619f7dc1657b0666 Mon Sep 17 00:00:00 2001 From: ylzou Date: Tue, 27 Jul 2021 16:37:17 +0100 Subject: [PATCH 03/11] =?UTF-8?q?Update=200435.=E6=97=A0=E9=87=8D=E5=8F=A0?= =?UTF-8?q?=E5=8C=BA=E9=97=B4.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Java，按左边排序，不管右边顺序。相交的时候取最小的右边。 --- problems/0435.无重叠区间.md | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/problems/0435.无重叠区间.md b/problems/0435.无重叠区间.md index 37bb0b5d..d32c2ebb 100644 --- a/problems/0435.无重叠区间.md +++ b/problems/0435.无重叠区间.md @@ -211,6 +211,29 @@ class Solution { } ``` +Java: +按左边排序，不管右边顺序。相交的时候取最小的右边。 +```java +class Solution { + public int eraseOverlapIntervals(int[][] intervals) { + + Arrays.sort(intervals,(a,b)->{ + return Integer.compare(a[0],b[0]); + }); + int remove = 0; + int pre = intervals[0][1]; + for(int i=1;iintervals[i][0]) { + remove++; + pre = Math.min(pre,intervals[i][1]); + } + else pre = intervals[i][1]; + } + return remove; + } +} +``` + Python： ```python class Solution: From 79fd10a6c498b5a3313738da41e653ccb1ab4580 Mon Sep 17 00:00:00 2001 From: posper Date: Wed, 28 Jul 2021 14:13:51 +0800 Subject: [PATCH 04/11] =?UTF-8?q?283.=20=E7=A7=BB=E5=8A=A8=E9=9B=B6=20?= =?UTF-8?q?=E6=B7=BB=E5=8A=A0Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0283.移动零.md | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/problems/0283.移动零.md b/problems/0283.移动零.md index 56f96b2f..8db42a0a 100644 --- a/problems/0283.移动零.md +++ b/problems/0283.移动零.md @@ -64,6 +64,21 @@ public: Java： +```java +public void moveZeroes(int[] nums) { + int slow = 0; + for (int fast = 0; fast < nums.length; fast++) { + if (nums[fast] != 0) { + nums[slow++] = nums[fast]; + } + } + // 后面的元素全变成 0 + for (int j = slow; j < nums.length; j++) { + nums[j] = 0; + } + } +``` + Python： ```python From 8b15ec147c2027f48f4d211d0f7e1c8c1d26d7c6 Mon Sep 17 00:00:00 2001 From: posper Date: Wed, 28 Jul 2021 14:21:34 +0800 Subject: [PATCH 05/11] =?UTF-8?q?141.=20=E7=8E=AF=E5=BD=A2=E9=93=BE?= =?UTF-8?q?=E8=A1=A8=20=E6=B7=BB=E5=8A=A0Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0141.环形链表.md | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/problems/0141.环形链表.md b/problems/0141.环形链表.md index 4a40f953..0871202d 100644 --- a/problems/0141.环形链表.md +++ b/problems/0141.环形链表.md @@ -14,7 +14,7 @@ 如果链表中有某个节点，可以通过连续跟踪 next 指针再次到达，则链表中存在环。 为了表示给定链表中的环，我们使用整数 pos 来表示链表尾连接到链表中的位置（索引从 0 开始）。 如果 pos 是 -1，则在该链表中没有环。注意：pos 不作为参数进行传递，仅仅是为了标识链表的实际情况。 如果链表中存在环，则返回 true 。 否则，返回 false 。 -  + ![](https://code-thinking-1253855093.file.myqcloud.com/pics/20210727173600.png) # 思路 @@ -74,6 +74,21 @@ public: ## Java ```java +public class Solution { + public boolean hasCycle(ListNode head) { + ListNode fast = head; + ListNode slow = head; + // 空链表、单节点链表一定不会有环 + while (fast != null && fast.next != null) { + fast = fast.next.next; // 快指针，一次移动两步 + slow = slow.next; // 慢指针，一次移动一步 + if (fast == slow) { // 快慢指针相遇，表明有环 + return true; + } + } + return false; // 正常走到链表末尾，表明没有环 + } +} ``` ## Python From 3be442c833eb21e1d7084cc44a898bf4ef951627 Mon Sep 17 00:00:00 2001 From: posper Date: Wed, 28 Jul 2021 14:47:26 +0800 Subject: [PATCH 06/11] =?UTF-8?q?0941.=E6=9C=89=E6=95=88=E7=9A=84=E5=B1=B1?= =?UTF-8?q?=E8=84=89=E6=95=B0=E7=BB=84=20=E6=B7=BB=E5=8A=A0Java=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/0941.有效的山脉数组.md | 31 ++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) diff --git a/problems/0941.有效的山脉数组.md b/problems/0941.有效的山脉数组.md index 6dbc3da2..167cfb1a 100644 --- a/problems/0941.有效的山脉数组.md +++ b/problems/0941.有效的山脉数组.md @@ -18,7 +18,7 @@ https://leetcode-cn.com/problems/valid-mountain-array/ C++代码如下： -``` +```c++ class Solution { public: bool validMountainArray(vector& A) { @@ -38,6 +38,33 @@ public: } }; ``` +Java 版本如下： + +```java +class Solution { + public boolean validMountainArray(int[] arr) { + if (arr.length < 3) { // 此时，一定不是有效的山脉数组 + return false; + } + // 双指针 + int left = 0; + int right = arr.length - 1; + // 注意防止指针越界 + while (left + 1 < arr.length && arr[left] < arr[left + 1]) { + left++; + } + // 注意防止指针越界 + while (right > 0 && arr[right] < arr[right - 1]) { + right--; + } + // 如果left或者right都在起始位置，说明不是山峰 + if (left == right && left != 0 && right != arr.length - 1) { + return true; + } + return false; + } +} +``` + 如果想系统学一学双指针的话， 可以看一下这篇[双指针法：总结篇！](https://mp.weixin.qq.com/s/_p7grwjISfMh0U65uOyCjA) - From 32ffbe028816905ea510472d72d40aae7bd4fb4f Mon Sep 17 00:00:00 2001 From: posper Date: Wed, 28 Jul 2021 15:08:14 +0800 Subject: [PATCH 07/11] =?UTF-8?q?34.=20=E5=9C=A8=E6=8E=92=E5=BA=8F?= =?UTF-8?q?=E6=95=B0=E7=BB=84=E4=B8=AD=E6=9F=A5=E6=89=BE=E5=85=83=E7=B4=A0?= =?UTF-8?q?=E7=9A=84=E7=AC=AC=E4=B8=80=E4=B8=AA=E5=92=8C=E6=9C=80=E5=90=8E?= =?UTF-8?q?=E4=B8=80=E4=B8=AA=E4=BD=8D=E7=BD=AE=EF=BC=8C=E6=B7=BB=E5=8A=A0?= =?UTF-8?q?Java=E7=89=88=E6=9C=AC&=E8=A7=A3=E6=B3=952?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...元素的第一个和最后一个位置.md | 100 +++++++++++++++++- 1 file changed, 98 insertions(+), 2 deletions(-) diff --git a/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md b/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md index 04f5eaf7..97b9a9b6 100644 --- a/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md +++ b/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md @@ -14,7 +14,7 @@ 如果数组中不存在目标值 target，返回 [-1, -1]。 进阶：你可以设计并实现时间复杂度为 O(log n) 的算法解决此问题吗？ -  + 示例 1： * 输入：nums = [5,7,7,8,8,10], target = 8 @@ -173,8 +173,105 @@ private: ## Java ```java +class Solution { + int[] searchRange(int[] nums, int target) { + int leftBorder = getLeftBorder(nums, target); + int rightBorder = getRightBorder(nums, target); + // 情况一 + if (leftBorder == -2 || rightBorder == -2) return new int[]{-1, -1}; + // 情况三 + if (rightBorder - leftBorder > 1) return new int[]{leftBorder + 1, rightBorder - 1}; + // 情况二 + return new int[]{-1, -1}; + } + + int getRightBorder(int[] nums, int target) { + int left = 0; + int right = nums.length - 1; + int rightBorder = -2; // 记录一下rightBorder没有被赋值的情况 + while (left <= right) { + int middle = left + ((right - left) / 2); + if (nums[middle] > target) { + right = middle - 1; + } else { // 寻找右边界，nums[middle] == target的时候更新left + left = middle + 1; + rightBorder = left; + } + } + return rightBorder; + } + + int getLeftBorder(int[] nums, int target) { + int left = 0; + int right = nums.length - 1; + int leftBorder = -2; // 记录一下leftBorder没有被赋值的情况 + while (left <= right) { + int middle = left + ((right - left) / 2); + if (nums[middle] >= target) { // 寻找左边界，nums[middle] == target的时候更新right + right = middle - 1; + leftBorder = right; + } else { + left = middle + 1; + } + } + return leftBorder; + } +} ``` +```java +// 解法2 +// 1、首先，在 nums 数组中二分查找 target； +// 2、如果二分查找失败，则 binarySearch 返回 -1，表明 nums 中没有 target。此时，searchRange 直接返回 {-1, -1}； +// 3、如果二分查找失败，则 binarySearch 返回 nums 中 为 target 的一个下标。然后，通过左右滑动指针，来找到符合题意的区间 + +class Solution { + public int[] searchRange(int[] nums, int target) { + int index = binarySearch(nums, target); // 二分查找 + + if (index == -1) { // nums 中不存在 target，直接返回 {-1, -1} + return new int[] {-1, -1}; // 匿名数组 + } + // nums 中存在 targe，则左右滑动指针，来找到符合题意的区间 + int left = index; + int right = index; + // 向左滑动，找左边界 + while (left - 1 >= 0 && nums[left - 1] == nums[index]) { // 防止数组越界。逻辑短路，两个条件顺序不能换 + left--; + } + // 向左滑动，找右边界 + while (right + 1 < nums.length && nums[right + 1] == nums[index]) { // 防止数组越界。 + right++; + } + return new int[] {left, right}; + } + + /** + * 二分查找 + * @param nums + * @param target + */ + public int binarySearch(int[] nums, int target) { + int left = 0; + int right = nums.length - 1; // 不变量：左闭右闭区间 + + while (left <= right) { // 不变量：左闭右闭区间 + int mid = left + (right - left) / 2; + if (nums[mid] == target) { + return mid; + } else if (nums[mid] < target) { + left = mid + 1; + } else { + right = mid - 1; // 不变量：左闭右闭区间 + } + } + return -1; // 不存在 + } +} +``` + + + ## Python ```python @@ -196,4 +293,3 @@ private: * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
- From b6424893b3bfc25b8f4824f5ba994641e708b176 Mon Sep 17 00:00:00 2001 From: posper Date: Wed, 28 Jul 2021 15:25:16 +0800 Subject: [PATCH 08/11] =?UTF-8?q?1207.=E7=8B=AC=E4=B8=80=E6=97=A0=E4=BA=8C?= =?UTF-8?q?=E7=9A=84=E5=87=BA=E7=8E=B0=E6=AC=A1=E6=95=B0=20=E6=B7=BB?= =?UTF-8?q?=E5=8A=A0Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/1207.独一无二的出现次数.md | 23 +++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/problems/1207.独一无二的出现次数.md b/problems/1207.独一无二的出现次数.md index 377d9ebf..c1720430 100644 --- a/problems/1207.独一无二的出现次数.md +++ b/problems/1207.独一无二的出现次数.md @@ -77,6 +77,28 @@ public: Java： +```java +class Solution { + public boolean uniqueOccurrences(int[] arr) { + int[] count = new int[2002]; + for (int i = 0; i < arr.length; i++) { + count[arr[i] + 1000]++; // 防止负数作为下标 + } + boolean[] flag = new boolean[1002]; // 标记相同频率是否重复出现 + for (int i = 0; i <= 2000; i++) { + if (count[i] > 0) { + if (flag[count[i]] == false) { + flag[count[i]] = true; + } else { + return false; + } + } + } + return true; + } +} +``` + Python： Go： @@ -89,4 +111,3 @@ JavaScript： * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
- From e7f772afb4425f65d6821667ba78aa3edb52f2fc Mon Sep 17 00:00:00 2001 From: fixme Date: Wed, 28 Jul 2021 22:49:01 +0800 Subject: [PATCH 09/11] =?UTF-8?q?=E5=A2=9E=E5=8A=A0c=E5=AE=9E=E7=8E=B0?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0203.移除链表元素.md | 31 +++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/problems/0203.移除链表元素.md b/problems/0203.移除链表元素.md index cac9f233..ea1d705a 100644 --- a/problems/0203.移除链表元素.md +++ b/problems/0203.移除链表元素.md @@ -146,8 +146,39 @@ public: ## 其他语言版本 +C: +```c +/** + * Definition for singly-linked list. + * struct ListNode { + * int val; + * struct ListNode *next; + * }; + */ +struct ListNode* removeElements(struct ListNode* head, int val){ + typedef struct ListNode ListNode; + ListNode *shead; + shead = (ListNode *)malloc(sizeof(ListNode)); + shead->next = head; + ListNode *cur = shead; + while(cur->next != NULL){ + if (cur->next->val == val){ + ListNode *tmp = cur->next; + cur->next = cur->next->next; + free(tmp); + } + else{ + cur = cur->next; + } + } + head = shead->next; + free(shead); + return head; +} +``` + Java： ```java /** From c75b29bc04c71063266cfbcec97c3398e1d3ef98 Mon Sep 17 00:00:00 2001 From: kok-s0s <2694308562@qq.com> Date: Wed, 28 Jul 2021 23:46:46 +0800 Subject: [PATCH 10/11] =?UTF-8?q?=E6=8F=90=E4=BE=9BJavaScript=E7=89=88?= =?UTF-8?q?=E6=9C=AC=E7=9A=84=E3=80=8A=E5=AE=9E=E7=8E=B0strStr()=E3=80=8B?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0028.实现strStr.md | 86 +++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) diff --git a/problems/0028.实现strStr.md b/problems/0028.实现strStr.md index 69f8c9d6..fc14a34a 100644 --- a/problems/0028.实现strStr.md +++ b/problems/0028.实现strStr.md @@ -808,7 +808,93 @@ func strStr(haystack string, needle string) int { } ``` +JavaScript版本 +> 前缀表统一减一 + +```javascript +/** + * @param {string} haystack + * @param {string} needle + * @return {number} + */ +var strStr = function (haystack, needle) { + if (needle.length === 0) + return 0; + + const getNext = (needle) => { + let next = []; + let j = -1; + next.push(j); + + for (let i = 1; i < needle.length; ++i) { + while (j >= 0 && needle[i] !== needle[j + 1]) + j = next[j]; + if (needle[i] === needle[j + 1]) + j++; + next.push(j); + } + + return next; + } + + let next = getNext(needle); + let j = -1; + for (let i = 0; i < haystack.length; ++i) { + while (j >= 0 && haystack[i] !== needle[j + 1]) + j = next[j]; + if (haystack[i] === needle[j + 1]) + j++; + if (j === needle.length - 1) + return (i - needle.length + 1); + } + + return -1; +}; +``` + +> 前缀表统一不减一 + +```javascript +/** + * @param {string} haystack + * @param {string} needle + * @return {number} + */ +var strStr = function (haystack, needle) { + if (needle.length === 0) + return 0; + + const getNext = (needle) => { + let next = []; + let j = 0; + next.push(j); + + for (let i = 1; i < needle.length; ++i) { + while (j > 0 && needle[i] !== needle[j]) + j = next[j - 1]; + if (needle[i] === needle[j]) + j++; + next.push(j); + } + + return next; + } + + let next = getNext(needle); + let j = 0; + for (let i = 0; i < haystack.length; ++i) { + while (j > 0 && haystack[i] !== needle[j]) + j = next[j - 1]; + if (haystack[i] === needle[j]) + j++; + if (j === needle.length) + return (i - needle.length + 1); + } + + return -1; +}; +``` From 3dcaa43ffe0e6b585e0eb2c372ea7786c1e7cca6 Mon Sep 17 00:00:00 2001 From: kok-s0s <2694308562@qq.com> Date: Wed, 28 Jul 2021 23:48:27 +0800 Subject: [PATCH 11/11] =?UTF-8?q?=E6=8F=90=E4=BE=9BJavaScript=E7=89=88?= =?UTF-8?q?=E6=9C=AC=E7=9A=84=E3=80=8A=E9=87=8D=E5=A4=8D=E7=9A=84=E5=AD=90?= =?UTF-8?q?=E5=AD=97=E7=AC=A6=E4=B8=B2=E3=80=8B?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0459.重复的子字符串.md | 71 ++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/problems/0459.重复的子字符串.md b/problems/0459.重复的子字符串.md index f012811d..25b52e86 100644 --- a/problems/0459.重复的子字符串.md +++ b/problems/0459.重复的子字符串.md @@ -289,8 +289,79 @@ func repeatedSubstringPattern(s string) bool { } ``` +JavaScript版本 +> 前缀表统一减一 +```javascript +/** + * @param {string} s + * @return {boolean} + */ +var repeatedSubstringPattern = function (s) { + if (s.length === 0) + return false; + + const getNext = (s) => { + let next = []; + let j = -1; + + next.push(j); + + for (let i = 1; i < s.length; ++i) { + while (j >= 0 && s[i] !== s[j + 1]) + j = next[j]; + if (s[i] === s[j + 1]) + j++; + next.push(j); + } + + return next; + } + + let next = getNext(s); + + if (next[next.length - 1] !== -1 && s.length % (s.length - (next[next.length - 1] + 1)) === 0) + return true; + return false; +}; +``` + +> 前缀表统一不减一 + +```javascript +/** + * @param {string} s + * @return {boolean} + */ +var repeatedSubstringPattern = function (s) { + if (s.length === 0) + return false; + + const getNext = (s) => { + let next = []; + let j = 0; + + next.push(j); + + for (let i = 1; i < s.length; ++i) { + while (j > 0 && s[i] !== s[j]) + j = next[j - 1]; + if (s[i] === s[j]) + j++; + next.push(j); + } + + return next; + } + + let next = getNext(s); + + if (next[next.length - 1] !== 0 && s.length % (s.length - next[next.length - 1]) === 0) + return true; + return false; +}; +```