代码随想录

代码随想录
代码随想录CSDN官方

主要题目

344. 反转字符串

https://leetcode.cn/problems/reverse-string/description/

var reverseString = function(s) {for(let i=0,j=s.length-1;i<j;i++,j--){[s[i],s[j]]=[s[j],s[i]]}
};

541. 反转字符串 II

https://leetcode.cn/problems/reverse-string-ii/description/

注意：

• js的字符串是常量，是不能在字符串上修改的
• 因此这里要把字符串拆成数组，s.split
• 最后再把数组拼回字符串，s.join

/*** @param {string} s* @param {number} k* @return {string}*/
var reverseStr = function (s, k) {const len = s.length;let arr = s.split('');for (let i = 0; i < len; i += 2 * k) {let l = i, r = l + k - 1 > len - 1 ? len - 1 : l + k - 1;while (l < r) {[arr[l], arr[r]] = [arr[r], arr[l]]l++, r--}}return arr.join('');
};

剑指 Offer 05. 替换空格

https://leetcode.cn/problems/ti-huan-kong-ge-lcof/description/

/*** @param {string} s* @return {string}*/
var replaceSpace = function (s) {let num = 0;let arr = [];for (let i = 0; i < s.length; i++) {if (s[i] == ' ') arr.push('%20')else arr.push(s[i])}return arr.join('');
};

151. 反转字符串中的单词

https://leetcode.cn/problems/reverse-words-in-a-string/

注意：会有多个空格，而字符串中的空格在split后为''

/*** @param {string} s* @return {string}*/// 在数组中去除多余空格
var space = function (arr) {let arr1 = []for (let i = 0; i < arr.length; i++) {if (arr[i] != '') {arr1.push(arr[i])}}return arr1;
}var reverseWords = function (s) {let arr = s.split(' ');let arr1 = space(arr)for (let i = 0, j = arr1.length - 1; i < j; i++, j--) {[arr1[i], arr1[j]] = [arr1[j], arr1[i]]}return arr1.join(" ")
};

剑指 Offer 58 - II. 左旋转字符串

https://leetcode.cn/problems/zuo-xuan-zhuan-zi-fu-chuan-lcof/description/

var reverseLeftWords = function (s, n) {for (let i = 0; i < n; i++) {s += s[i]}return s.slice(n);
};

28. 找出字符串中第一个匹配项的下标（KMP）还没写

https://leetcode.cn/problems/find-the-index-of-the-first-occurrence-in-a-string/

459.重复的子字符串（KMP）还没写

https://leetcode.cn/problems/repeated-substring-pattern/