刷题汇总（一）leetcode 精选50题 JavaScript答案总结

题目来源

腾讯精选练习（50 题）
信息更新时间：2019-3-11，因为要准备面前端，就用js做了遍来熟悉JavaScript这门语言，50道题均已提交通过。

GitHub地址：https://github.com/zj19941113/LeetCode-50-JavaScript-Answers

相关：
刷题汇总（二）剑指Offer 66题 C++答案总结
刷题汇总（三）leetcode 精选50题 C++答案总结
刷题汇总（四）技术类编程题汇总 C++
刷题汇总（五）leetcode 热题 HOT 100 C++ 答案总结
刷题汇总（六）leetcode 多线程 / Shell

2两数相加-33.0%-中等

https://leetcode-cn.com/problems/add-two-numbers/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*/
/*** @param {ListNode} l1* @param {ListNode} l2* @return {ListNode}*/
var addTwoNumbers = function(l1, l2) {var re = new ListNode(0); //0随便取，不会用到，只为了初始化var r=re;  //浅拷贝var carry=0;while(l1!=null || l2!=null){var x = l1==null? 0:l1.val;var y = l2==null? 0:l2.val;r.next=new ListNode((carry+x+y)%10);r=r.next;if(carry+x+y>9){carry=1;}else{carry=0;}if(l1!=null){l1=l1.next;}if(l2!=null){l2=l2.next;}}if(carry>0){r.next=new ListNode(1); //最高位进1} return re.next;
};

4寻找两个有序数组的中位数-33.8%-困难

https://leetcode-cn.com/problems/median-of-two-sorted-arrays/

/*** @param {number[]} nums1* @param {number[]} nums2* @return {number}*/
var findMedianSortedArrays = function(a, b) {// 谁小谁移，移动k次，k中间var n = a.length;var m = b.length;var nm = n + m;var ni = 0,mi = 0,x,y; while(ni + mi < nm ){  if(ni < n ){while(mi == m || a[ni] <= b[mi]){ni=ni+1;if(ni+mi == (nm+1)/2){ //总长奇return a[ni-1];}if(ni+mi == nm/2){//总长偶x = a[ni-1];break;}if(ni+mi == (nm/2 + 1)){ y = a[ni-1];return (x+y)/2}}}if(mi < m){while(ni == n || b[mi] <= a[ni]){mi = mi + 1;if(ni+mi == (nm+1)/2){return b[mi-1];}if(ni+mi == nm/2){x = b[mi-1];}if(ni+mi == (nm/2 + 1)){ y = b[mi-1];return (x+y)/2}}}}return -1;
};

5最长回文子串-24.7%-中等

https://leetcode-cn.com/problems/longest-palindromic-substring/submissions/

/*** @param {string} s* @return {string}*/
var longestPalindrome = function(s) {if (s==null&&s.length<1){return "";}var fir = 0;var las = 0;for(var i=0;i<s.length;i++){var lenl = getsub(s,i,i);var lenr = getsub(s,i,i+1);var len = Math.max(lenl,lenr);if(len>las-fir){fir = i - Math.floor((len-1)/2);las = i + Math.floor(len/2);}     }return s.slice(fir,las+1);
};function getsub(s,l,r){while(l>=0&&r<=s.length-1&&s.charAt(l)==s.charAt(r)){l--;r++;}return r-l-1;
}

7整数反转-31.8%-简单

https://leetcode-cn.com/problems/reverse-integer/

/*** @param {number} x* @return {number}*/
var reverse = function(x) {var result = 0;var strx;var mayAns;if(x>0){strx = String(x);mayAns = Number(strx.split("").reverse().join(""));return mayAns<=Math.pow(2,31)-1?mayAns:0;}else{strx = String(-x);mayAns = -Number(strx.split("").reverse().join(""));return mayAns>=-Math.pow(2,31) ?mayAns:0;}return result;
};

8字符串转换整数 (atoi)-16.6%-中等

https://leetcode-cn.com/problems/median-of-two-sorted-arrays

/*** @param {string} str* @return {number}*/
var myAtoi = function(str) {str = str.trim();var word = str.split(" ")[0];if(parseInt(word)){if(parseInt(word)>Math.pow(2,31)-1){return Math.pow(2,31)-1;};if(parseInt(word)<-Math.pow(2,31)){return -Math.pow(2,31);};return parseInt(word);}return 0;
};

9回文数-56.0%-简单

https://leetcode-cn.com/problems/palindrome-number/

/*** @param {number} x* @return {boolean}*/
var isPalindrome = function(x) {if(x >= 0){var strx = String(x); return strx == strx.split("").reverse().join("");}return false;
};

11盛最多水的容器-53.5%-中等

https://leetcode-cn.com/problems/container-with-most-water/

/*** @param {number[]} height* @return {number}*/
var maxArea = function(height) {var maxs = 0;for (var i=0;i<height.length;i++){for (var j=i+1;j<height.length;j++){var tmp = Math.min(height[i],height[j])*(j-i);if(tmp>maxs){maxs = tmp;}}}return maxs;
};

14最长公共前缀-32.2%-简单

https://leetcode-cn.com/problems/longest-common-prefix/

/*** @param {string[]} strs* @return {string}*/
var longestCommonPrefix = function(strs) {if(strs.length == 0){return "";}var mini = 0;for(var i=1;i<strs.length;i++){if (strs[i].length<strs[mini].length){mini = i;}}var result = "";for(let j=0;j<strs[mini].length;j++){for( i=0;i<strs.length;i++){if(strs[mini].slice(0,j+1) != strs[i].slice(0,j+1)){return result;}}result =  strs[mini].slice(0,j+1); }return result;
};

15三数之和-21.2%-中等

https://leetcode-cn.com/problems/3sum

/*** @param {number[]} nums* @return {number[][]}*/
var threeSum = function(nums) {nums.sort(function(a,b){return a-b});var ls = [];for (var i=0;i<nums.length-2;i++) {if(nums[i]==nums[i-1]){ //i和前面一样，跳过continue;}for (var j=i+1;j<nums.length-1;j++) {if(nums[j]==nums[j-1]&&j!=i+1){ //j和前面一样，且前面不是i，跳过continue;}for (var k=j+1;k<nums.length;k++) {if(nums[k]+nums[j]+nums[i] == 0){ls.push([nums[i],nums[j],nums[k]]); //找到k跳出，不再往后break;}}}}return ls;
};

16最接近的三数之和-39.0%-中等

https://leetcode-cn.com/problems/3sum-closest/

/*** @param {number[]} nums* @param {number} target* @return {number}*/
var threeSumClosest = function(nums, target) {var len = nums.length;var minl = nums[0]+nums[1]+nums[2];for(var i=0;i<len-2;i++){for(var j=i+1;j<len-1;j++){for(var k=j+1;k<len;k++){var tmp = nums[i]+nums[j]+nums[k];if(Math.abs(tmp-target)<Math.abs(minl-target)){minl = tmp;}}}}return minl;
};

20有效的括号-36.7%-简单

https://leetcode-cn.com/problems/valid-parentheses/

/*** @param {string} s* @return {boolean}*/
var isValid = function(s) {if(s == null||s.length <1){return true;}var stack = [];for(var i=0;i<s.length;i++){if(s[i] == ""){continue;}if(stack.leng<1){stack.push(s[i]);}else if(stack[stack.length-1]=="("&&s[i]==")" ||stack[stack.length-1]=="{"&&s[i]=="}" ||stack[stack.length-1]=="["&&s[i]=="]"){stack.pop();}else{stack.push(s[i]);}}return stack.length<1;
};

21合并两个有序链表-52.9%-简单

https://leetcode-cn.com/problems/merge-two-sorted-lists/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*/
/*** @param {ListNode} l1* @param {ListNode} l2* @return {ListNode}*/
var mergeTwoLists = function(l1, l2) {var l3 = new ListNode(0);var l4 = l3;while(l1!=null && l2!=null){if(l1.val<l2.val){l4.next = l1;l1 = l1.next;}else{l4.next = l2;l2 = l2.next;}l4 = l4.next;}l4.next = l1==null?l2:l1;return l3.next;
};

23合并K个排序链表-43.8%-困难

https://leetcode-cn.com/problems/merge-k-sorted-lists/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*/
/*** @param {ListNode[]} lists* @return {ListNode}*/
var mergeKLists = function(lists) {var rl = null;for(var i=0;i<lists.length;i++){rl = mergeTwoLists(lists[i],rl);}return rl;
};var mergeTwoLists = function(l1, l2) {var l3 = new ListNode(0);var l4 = l3;while(l1!=null && l2!=null){if(l1.val<l2.val){l4.next = l1;l1 = l1.next;}else{l4.next = l2;l2 = l2.next;}l4 = l4.next;}l4.next = l1==null?l2:l1;return l3.next;
};

26删除排序数组中的重复项-42.9%-简单

https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array/

/*** @param {number[]} nums* @return {number}*/
var removeDuplicates = function(nums) {for(var i=0;i<nums.length;i++){var j=1;while(nums[i] == nums[i+j]){++j;}if(j!=1){nums.splice(i,j-1);}}return nums.length;
};

33搜索旋转排序数组-35.8%-中等

https://leetcode-cn.com/problems/search-in-rotated-sorted-array/

/*** @param {number[]} nums* @param {number} target* @return {number}*/
var search = function(nums, target) {return searchs(nums, 0, nums.length-1, target);
};function searchs(nums,l,h,target){//搜不到返回-1，搜到了返回targetif (l > h){return -1;} var mid = Math.floor((l + h)/2);//[0,1,2,4,5,6,7]if(nums[mid] == target){return mid;}if(nums[mid] < nums[h]){ //旋转在左 [6,7,0,1,2,4,5]if(nums[mid]<target&&target<=nums[h]){ return searchs(nums,mid+1,h,target);//在右，右顺序}else{return searchs(nums,l,mid-1,target);//不在右}}else{ //旋转在右 [2,4,5,6,7,0,1]if(nums[l]<=target&&target<nums[mid]){ return searchs(nums,l,mid-1,target);//在左，左顺序}else{return searchs(nums,mid+1,h,target);//不在右}}
}

43字符串相乘-37.9%-中等

https://leetcode-cn.com/problems/multiply-strings/

/*** @param {string} num1* @param {string} num2* @return {string}*/
var multiply = function(num1, num2) {var res = "";var len1 = num1.length;var len2 = num2.length;for(var i=0;i<len1;i++){for(var j=0;j<len2;j++){var base = Array(i+j+1).join(0);//i+j个0  eg:"00"  //逐位相乘var tmp = String(Number(num1[len1-1-i])*Number(num2[len2-1-j])) + base;res = addstr(res,tmp);}}while(res[0] == 0 && res.length > 1){//"002" -> "2"res = res.slice(1);}return res;
};function addstr(s1, s2) { //字符串相加var re = "";if(s1.length>=s2.length){s2 =  Array(s1.length-s2.length+1).join(0) + s2;}else{s1 = Array(s2.length-s1.length+1).join(0) + s1;}var flag = 0;for(let i=0;i<s1.length;i++){var t = Number(s1[s1.length - 1 - i]) + Number(s2[s1.length - 1 - i]) + flag;if(t < 10){re = String(t).concat(re);flag = 0;}else{re = String(t-10).concat(re);flag = 1;}}return flag == 0? re:"1"+re;
};

46全排列-66.7%-中等

https://leetcode-cn.com/problems/permutations/

/*** @param {number[]} nums* @return {number[][]}*/
var permute = function(nums) {if(nums.length == 0){return [[]];}if(nums.length == 1){var re = [];re.push(nums);return re;}var nums1 = permute(nums.slice(1));var num0 = nums[0];var result = [];for(var i=0;i<nums1.length;i++){for(var j=0;j<nums1[i].length+1;j++){var tmp = nums1[i].concat();tmp.splice(j,0,num0);result.push(tmp);}}return result;
};

53最大子序和-42.9%-简单

https://leetcode-cn.com/problems/maximum-subarray/

/*** @param {number[]} nums* @return {number}*/
var maxSubArray = function(nums) {var sum = 0;var maxsum = nums[0];for(var i=0;i<nums.length;i++){sum +=nums[i];if(sum > maxsum){maxsum = sum;} if(sum < 0){sum = 0;}}return maxsum;
};

54螺旋矩阵-34.0%-中等

https://leetcode-cn.com/problems/spiral-matrix/

/*** @param {number[][]} matrix* @return {number[]}*/
var spiralOrder = function(matrix) {var arr = [];while(!(matrix.length == 0||matrix[0].length == 0)){var tmp = matrix.shift(); //剪第一行arr = arr.concat(tmp);if(matrix.length == 0||matrix[0].length == 0){ //[]   [[],[]]return arr;}for(var i=0;i<matrix.length;i++){//剪最后一列var tmp = matrix[i].pop();arr.push(tmp);}if(matrix.length == 0||matrix[0].length == 0){return arr;}var tmp = matrix.pop().reverse();//剪最后一行arr = arr.concat(tmp);if(matrix.length == 0||matrix[0].length == 0){return arr;}for(var i=0;i<matrix.length;i++){//剪第一列var tmp = matrix[matrix.length-1-i].shift();arr.push(tmp);}}return arr;
};

59螺旋矩阵II-71.1%-中等

https://leetcode-cn.com/problems/spiral-matrix-ii/

/*** @param {number} n* @return {number[][]}*/
var generateMatrix = function(n) {var arr = [];for(var i = 0; i < n; i++) {arr.push(new Array(n).fill(0));//创建n*n零矩阵}var c = 1;var i = 0;while(c <= n*n){for(var j=i;j<n-i;j++){//第一行arr[i][j] = c++;}for(var j=i+1;j<n-i;j++){//最后一列arr[j][n-i-1] = c++;}for(var j=i+1;j<n-i;j++){//最后一行arr[n-i-1][n-j-1] = c++;}for(var j=i+1;j<n-i-1;j++){//第一列arr[n-j-1][i] = c++;}i++;}return arr;
};

61旋转链表-37.5%-中等

https://leetcode-cn.com/problems/rotate-list/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*/
/*** @param {ListNode} head* @param {number} k* @return {ListNode}*/
var rotateRight = function(head, k) {if(head == null||k==0){return head;}var h = head;var len = 1;//总长while(h.next !=null ){++len;h = h.next;}if(k % len == 0){//不用旋转 head本身return head;}if(k > len){//需旋转k = k % len;}len = len - k;var ln = new ListNode(0);//0->1->2->3->NULLvar n = ln; while(len != 0){n.next = head;n = n.next;head = head.next;--len;}n.next = null;var r = head;var lr = r;while(head.next != null){lr = head;head = head.next;lr = lr.next;}lr.next = ln.nextreturn r;
};

62不同路径-52.6%-中等

https://leetcode-cn.com/problems/unique-paths/

/*** @param {number} m* @param {number} n* @return {number}*/
var uniquePaths = function(m, n) {var dp = [];for(var i=0;i<m;i++){ //创建m*n零矩阵dp.push(new Array(n).fill(0));}for(var i=0;i<m;i++){for(var j=0;j<n;j++){if(i==0||j==0){dp[i][j] = 1;}else{dp[i][j] = dp[i-1][j]+dp[i][j-1]}}}return dp[m-1][n-1];
};

70爬楼梯-44.5%-简单

https://leetcode-cn.com/problems/climbing-stairs/

/*** @param {number} n* @return {number}*/
var climbStairs = function(n) {if(n==1){return 1;}if(n==2){return 2;}var i = 1;var j = 2;for(var k=0;k<n-2;k++){var tmp = i + j;i = j;j = tmp;}return j;
};

78子集-71.6%-中等

https://leetcode-cn.com/problems/subsets/

/*** @param {number[]} nums* @return {number[][]}*/
var subsets = function(nums) {var arr = [];arr.push([]);for(var i=0;i<nums.length;i++){var tmp = []; //tmp深拷贝arrfor(var k=0;k<arr.length;k++){tmp[k] = arr[k].slice(0);}for(var j=0;j<tmp.length;j++){tmp[j].push(nums[i]);arr.push(tmp[j]);}}return arr;
};

88合并两个有序数组-43.0%-简单

https://leetcode-cn.com/problems/merge-two-sorted-lists/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*/
/*** @param {ListNode} l1* @param {ListNode} l2* @return {ListNode}*/
var mergeTwoLists = function(l1, l2) {var l3 = new ListNode(0);var l4 = l3;while(l1!=null && l2!=null){if(l1.val<l2.val){l4.next = l1;l1 = l1.next;}else{l4.next = l2;l2 = l2.next;}l4 = l4.next;}l4.next = l1==null?l2:l1;return l3.next;
};

89格雷编码-62.7%-中等

https://leetcode-cn.com/problems/gray-code/

/*** @param {number} n* @return {number[]}*/
// 000 001 011 010  ——
//                    |
// 100 101 111 110 <——
var grayCode = function(n) {if(n == 0){return [0];}var tmp = grayCode(n-1).concat();//深拷贝for(var i=0;i<tmp.length;i++){tmp[i] += Math.pow(2,n-1);}tmp.reverse();return grayCode(n-1).concat(tmp);
};

104二叉树的最大深度-67.4%-简单

https://leetcode-cn.com/problems/maximum-depth-of-binary-tree/

/*** Definition for a binary tree node.* function TreeNode(val) {*     this.val = val;*     this.left = this.right = null;* }*/
/*** @param {TreeNode} root* @return {number}*/var maxDepth = function(root) {if(root == null){return 0;}var l_height = maxDepth(root.left);var r_height = maxDepth(root.right);return Math.max(l_height,r_height) + 1;
};

121买卖股票的最佳时机-48.5%-简单

https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock/

/*** @param {number[]} prices* @return {number}*/
var maxProfit = function(prices) {var maxtmp = 0;for(var i=0;i<prices.length;i++){  for(var j=i+1;j<prices.length;j++){ if(prices[j]-prices[i]>maxtmp){maxtmp = prices[j]-prices[i];}}   }return maxtmp;
};

122买卖股票的最佳时机II-51.6%-简单

https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-ii/

/*** @param {number[]} prices* @return {number}*/
var maxProfit = function(prices) {var maxtmp = 0;for(var i=0;i<prices.length-1;i++){  if (prices[i]<prices[i+1]){maxtmp += prices[i+1]-prices[i];}}return maxtmp;
};

124二叉树中的最大路径和-33.8%-困难

https://leetcode-cn.com/problems/binary-tree-maximum-path-sum/

/*** Definition for a binary tree node.* function TreeNode(val) {*     this.val = val;*     this.left = this.right = null;* }*/
/*** @param {TreeNode} root* @return {number}*/
var maxPathSum = function(root) {var len = -Number.MAX_VALUE;submax(root);function submax(t){if(t == null){return 0;}var l = Math.max(submax(t.left),0);var r = Math.max(submax(t.right),0);if(t.val + l + r > len){len = t.val + l + r;}return Math.max(l,r) + t.val;}return len;
};

136只出现一次的数字-59.1%-简单

https://leetcode-cn.com/problems/single-number/

/*** @param {number[]} nums* @return {number}*/
var singleNumber = function(nums) {// 交换律：a ^ b ^ c  <=> a ^ c ^ b,俩两相同的移到一起// 相同的数异或为0: n ^ n => 0,只剩下单个的了// 任何数于0异或为任何数 0 ^ n => nvar s = 0;for(var i=0;i<nums.length;i++){s = s^nums[i];}return s;
};

141环形链表-35.5%-简单

https://leetcode-cn.com/problems/linked-list-cycle

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*//*** @param {ListNode} head* @return {boolean}*/
var hasCycle = function(head) {var slow = head, fast = head;while(fast && fast.next){slow = slow.next;fast = fast.next.next;if(slow == fast){return true;}}return false;
};

142环形链表II-34.8%-中等

https://leetcode-cn.com/problems/linked-list-cycle-ii/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*//*** @param {ListNode} head* @return {ListNode}*/
var detectCycle = function(head) {var slow = head,fast = head;var isloop = false;while(fast && fast.next){slow  = slow.next;fast = fast.next.next;if(slow == fast){//相遇isloop = true;break;}}if(isloop){var l  = head;while(l != slow){l = l.next;slow = slow.next;}return slow;}return null;
};

146LRU缓存机制-39.0%-困难

https://leetcode-cn.com/problems/lru-cache/

/*** @param {number} capacity*//**
1.新加入的数据————> ___ 头 <—————___          |___          |2.被访问的数据___     —————______<———— ___ 尾
3.淘汰的数据
*/var LRUCache = function(capacity) {this.size = capacity;this.map = {};this.list = [];
};/** * @param {number} key* @return {number}*/
LRUCache.prototype.get = function(key) {if(this.map[key] != null){this.list.splice(this.list.indexOf(key),1);//更新listthis.list.unshift(key);return this.map[key];}return -1;
};/** * @param {number} key * @param {number} value* @return {void}*/
LRUCache.prototype.put = function(key, value) {var tmp = this.list.indexOf(key);if(tmp != -1){ //key已存在，更新listthis.list.splice(tmp,1);}else{ //key不存在if(this.list.length == this.size){ //栈满var d = this.list.pop();this.map[d] = null;}   }this.list.unshift(key);this.map[key] = value;
};/** * Your LRUCache object will be instantiated and called as such:* var obj = Object.create(LRUCache).createNew(capacity)* var param_1 = obj.get(key)* obj.put(key,value)*/

148排序链表-58.6%-中等

https://leetcode-cn.com/problems/sort-list/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*/
/*** @param {ListNode} head* @return {ListNode}*/
var sortList = function(head) {if (!head || !head.next){return head;} var slow = head,bk = head,fast = head;while(fast && fast.next ){bk = slow;slow = slow.next;fast = fast.next.next;}bk.next = null;var l1 = sortList(head);//中分，归并var l2 = sortList(slow);return merge(l1,l2);
};function merge(l1,l2){//合并有序链表var l = new ListNode(0);var rl = l;while(l1 && l2){if(l1.val < l2.val){rl.next = l1;l1 = l1.next;}else{rl.next = l2;l2 = l2.next;}rl = rl.next;}rl.next = l1==null?l2:l1;return l.next;
}

155最小栈-47.7%-简单

https://leetcode-cn.com/problems/min-stack/

/*** initialize your data structure here.*/
var MinStack = function() {this.arr = [];
};/** * @param {number} x* @return {void}*/
MinStack.prototype.push = function(x) {this.arr.push(x);
};/*** @return {void}*/
MinStack.prototype.pop = function() {this.arr.pop();
};/*** @return {number}*/
MinStack.prototype.top = function() {return this.arr[this.arr.length-1];
};/*** @return {number}*/
MinStack.prototype.getMin = function() {return Math.min.apply( {}, this.arr );
};/** * Your MinStack object will be instantiated and called as such:* var obj = Object.create(MinStack).createNew()* obj.push(x)* obj.pop()* var param_3 = obj.top()* var param_4 = obj.getMin()*/

160相交链表-37.2%-简单

https://leetcode-cn.com/problems/intersection-of-two-linked-lists/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*//*** @param {ListNode} headA* @param {ListNode} headB* @return {ListNode}*/
var getIntersectionNode = function(headA, headB) {if(headA == null || headB == null){return null;}var pA = headA;var pB = headB;while(pA != pB) {pA = pA == null ? headB : pA.next;pB = pB == null ? headA : pB.next;}return pA;
};

169求众数-58.0%-简单

https://leetcode-cn.com/problems/majority-element/

/*** @param {number[]} nums* @return {number}*/
var majorityElement = function(nums) {nums.sort();return nums[Math.floor(nums.length/2)];
};

206反转链表-58.6%-简单

https://leetcode-cn.com/problems/reverse-linked-list/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*/
/*** @param {ListNode} head* @return {ListNode}*/
var reverseList = function(head) {var l  = null;while(head != null){var newl = new ListNode(head.val);var tmp = l;l = newl;l.next = tmp;head = head.next;}return l;
};

215数组中的第K个最大元素-56.6%-中等

https://leetcode-cn.com/problems/kth-largest-element-in-an-array/

/*** @param {number[]} nums* @param {number} k* @return {number}*/
var findKthLargest = function(nums, k) {return fastkmax(nums,0,nums.length-1,k);
};function fastkmax(n,l,r,k){var mid = partiton(n,l,r);//排序 左边都是比mid小的，右边都是比mid大的var rk = r - mid + 1;if(rk == k){return n[mid];}if(rk > k){return fastkmax(n,mid + 1,r,k);}return fastkmax(n,l,mid - 1,k -rk );
}function partiton(n,l,r){//一次快排var base = n[l];var i = l,j = r,tmp;while(i < j){while(n[j] >= base && i < j){j--;}while(n[i] <= base && i < j){i++;}tmp = n[i];n[i] = n[j];n[j] = tmp;}n[l] = n[i];n[i] = base;return i;}

217存在重复元素-47.0%-简单

https://leetcode-cn.com/problems/contains-duplicate/

/*** @param {number[]} nums* @return {boolean}*/
var containsDuplicate = function(nums) {nums.sort();for(var i=0;i<nums.length-1;i++){if(nums[i]==nums[i+1]){return true;}}return false;
};

230二叉搜索树中第K小的元素-62.0%-中等

https://leetcode-cn.com/problems/kth-smallest-element-in-a-bst/

/*** Definition for a binary tree node.* function TreeNode(val) {*     this.val = val;*     this.left = this.right = null;* }*/
/*** @param {TreeNode} root* @param {number} k* @return {number}*/
var kthSmallest = function(root, k) {var list = [];order(root,list);return list[k-1];
};
function order(root,list){//中序遍历if(!root){return;}order(root.left,list);list.push(root.val);order(root.right,list);
}

231 2的幂-44.3%-简单

https://leetcode-cn.com/problems/power-of-two/

/*** @param {number} n* @return {boolean}*/
var isPowerOfTwo = function(n) {if(n == 0){return false;}if(n == 1){return true;}return n%2==0?isPowerOfTwo(n/2):false;
};

235二叉搜索树的最近公共祖先-56.9%-简单

https://leetcode-cn.com/problems/lowest-common-ancestor-of-a-binary-search-tree/

/*** Definition for a binary tree node.* function TreeNode(val) {*     this.val = val;*     this.left = this.right = null;* }*/
/*** @param {TreeNode} root* @param {TreeNode} p* @param {TreeNode} q* @return {TreeNode}*/
var lowestCommonAncestor = function(root, p, q) {// 二叉搜索树(二叉排序树):若它的左子树不空，则左子树上所有结点的值均小于它的根结点的值;var res = null;lca(root, p , q);function lca(root, p, q){if((root.val - p.val)*(root.val - q.val) <= 0){ //root为p、q根节点res = root;}else if(root.val < p.val && root.val < q.val){ //都在右子树lca(root.right, p , q);}else{lca(root.left, p , q);}}return res;
};

236二叉树的最近公共祖先-50.4%-中等

https://leetcode-cn.com/problems/lowest-common-ancestor-of-a-binary-tree/

/*** Definition for a binary tree node.* function TreeNode(val) {*     this.val = val;*     this.left = this.right = null;* }*/
/*** @param {TreeNode} root* @param {TreeNode} p* @param {TreeNode} q* @return {TreeNode}*/
var lowestCommonAncestor = function(root, p, q) {if(!root){return null;}if(root == p || root == q){return root;}var l = lowestCommonAncestor(root.left,p,q)//左支存在一个的位置var r = lowestCommonAncestor(root.right,p,q)if(l && r){//左支有一个，右支有一个return root;}if(l){//右没有，都在左，先找到的即为根节点return l;}if(r){return r;}return null;
};

237删除链表中的节点-69.4%-简单

https://leetcode-cn.com/problems/delete-node-in-a-linked-list/

/*** Definition for singly-linked list.* function ListNode(val) {*     this.val = val;*     this.next = null;* }*/
/*** @param {ListNode} node* @return {void} Do not return anything, modify node in-place instead.*/
var deleteNode = function(node) {node.val = node.next.val;node.next = node.next.next;
};

238除自身以外数组的乘积-58.8%-中等

https://leetcode-cn.com/problems/product-of-array-except-self/

/*** @param {number[]} nums* @return {number[]}*/
var productExceptSelf = function(nums) {var arr = [];var l = 1, r = 1;for(var i=0;i<nums.length;i++){//arr[i] i左边数乘积arr[i] = l;l *= nums[i];}for(var j=nums.length-1;j>=0;j--){arr[j] *= r;r *= nums[j];}return arr;
};

292Nim游戏-66.4%-简单

https://leetcode-cn.com/problems/nim-game/

/*** @param {number} n* @return {boolean}*/
var canWinNim = function(n) {return n%4 == 0?false:true;
};

344反转字符串-65.1%-简单

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

/*** @param {character[]} s* @return {void} Do not return anything, modify s in-place instead.*/
var reverseString = function(s) {for(var i=1;i<s.length;i++){var tmp = s.splice(i,1)[0];s.unshift(tmp);}
};

557反转字符串中的单词III-63.5%-简单

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

/*** @param {string} s* @return {string}*/
var reverseWords = function(s) {var arr = s.split(" ");for(var i=0;i<arr.length;i++){arr[i] = arr[i].split("").reverse().join("");}return arr.join(" ");
};