背景记录一下，工作之所刷的 leetcode 题目。
01.twoSum/** * @param {number[]} nums * @param {number} target * @return {number[]} */var twoSum = function (nums, target) { for (var i = 1; i < nums.length; i++) { const idx = nums.indexOf(target - nums[i]); if (idx > -1 && idx !== i) { return [i, idx]; } } return [];};15.threeSum/** * @param {number[]} nums * @return {number[][]} */// Given array nums = [-1, 0, 1, 2, -1, -4],// A solution set is:// [// [-1, 0, 1],// [-1, -1, 2]// ]var threeSum = function (nums) { const result = []; const length = nums.length; if (length === 3) return [nums]; var sortedNums = num.sort((a, b) => a - b); for (let i = 0; i < l; i++) { if (i !== 0 && sortedNums[i] === sortedNums[i - 1]) continue; var j = i + 1; var k = l - 1; while (j < k) { var sum = temp[i] + temp[j] + temp[k]; if (sum === 0) { res.push([temp[i], temp[j], temp[k]]); while (j++ < k && temp[j - 1] === temp[j]) { /* do nothing*/ } while (k-- > j && temp[k] === temp[k + 1]) { /* do nothing*/ } } else if (sum < 0) { j++; } else { k--; } } } return result;};70.climbStairs/** * @param {number} n * @return {number} */var climbStairs = function (n) { const array = [0, 1, 2]; for (var i = 3; i <= n; i++) { array[i] = array[i - 1] + array[i - 2]; } return array[n];};283.moveZeroes/** * @param {number[]} nums * @return {void} Do not return anything, modify nums in-place instead. */var moveZeroes = function (nums) { var validNumberCount = 0; for (var i = 0; i < nums.length; i++) { if (nums[i] !== 0) { nums[validNumberCount] = nums[i]; validNumberCount++; } } for (var j = validNumberCount; j < nums.length; j++) { nums[j] = 0; } return nums;};11.maxArea/** * @param {number[]} height * @return {number} */// solution 1: 暴力双循环var maxArea = function (height) { var max = 0; for (var i = 0; i < height.length; i++) { for (var j = i + 1; j < height.length; j++) { max = Math.max(max, (j - i) * Math.min(height[i], height[j])); } } return max;};// solution 1: 双指针var maxArea = function (height) { var max = 0; var left = 0, right = height.length - 1; while (left < right) { var area = (right - left) * Math.min(height[left], height[right]); max = Math.max(max, area); if (height[left] < height[right]) { left++; } else { right--; } } return max;};84.largestRectangleArea/** * @param {number[]} heights * @return {number} */// ## 柱状图中最大的矩形// solution1: 暴力循环var largestRectangleArea = function (heights) { var maxArea = 0; for (var i = 0; i < heights.length; i++) { for (j = i; j < heights.length; j++) { var minHeight = Number.MAX_VALUE; for (var k = i; k <= j; k++) { minHeight += Math.min(minHeight, heights[k]); } maxArea = Math.max(maxArea, minHeight * (j - i + 1)); } } return maxArea;};// solution2: 最小栈// TODO239.maxSlidingWindow/* * @lc app=leetcode.cn id=239 lang=javascript * * [239] 滑动窗口最大值 */// @lc code=start/** * @param {number[]} nums * @param {number} k * @return {number[]} */// 解法1: 暴力var maxSlidingWindow = function (nums, k) { var length = nums.length; if (!length) return []; var res = []; for (var i = 0; i < length - (k - 1); i++) { let max = Number.MIN_SAFE_INTEGER; for (j = i; j < i + k; j++) { max = Math.max(max, nums[j]); } res.push(max); } return res;};// @lc code=end289.rotateArray/** * @param {number[]} nums * @param {number} k * @return {void} Do not return anything, modify nums in-place instead. */// solution 1: 暴力, 每次移动一个var rotate = function (nums, k) { let previous; for (var i = 0; i < k; i++) { previous = nums[nums.length - 1]; for (var j = 0; j < nums.length; j++) { [previous, nums[j]] = [nums[j], previous]; } }};88.mergeTwoArray/** * @param {number[]} nums1 * @param {number} m * @param {number[]} nums2 * @param {number} n * @return {void} Do not return anything, modify nums1 in-place instead. */// 解法1: 合并后排序var merge = function (nums1, m, nums2, n) { for (var i = 0; i < nums2.length; i++) { nums1[m + i] = nums2[i]; } nums1.sort((a, b) => a - b);};// 解法2: 判断元素大小, 直接插入var merge = function (nums1, m, nums2, n) { let length = m + n; while(n > 0) { if(m <= 0) { // num1中的元素已经排完， 剩下的nums直接放进来 nums1[--length] = nums2[--n]; continue; } nums1[--length] = nums1[m-1] > nums2[n-1] ? nums1[--m] : nums2[--n]; }};21.mergeTwoLists/** * 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) { if (l1 === null) return l2; if (l2 === null) return l1; if (l1.val < l2.val) { l1.next = mergeTwoLists(l1.next, l2); return l1; } else { l2.next = mergeTwoLists(l2.next, l1); return l2; }};42.trap 接雨水/** * @param {number[]} height * @return {number} */var trap = function (height) { let capacity = 0; const stack = []; for (let i = 0; i < height.length; i++) { while (stack.length !== 0 && height[stack[stack.length - 1]] < height[i]) { let cur = stack[stack.length - 1]; stack.pop(); if (stack.length === 0) { break; } let l = stack[stack.length - 1]; let r = i; capacity += (Math.min(height[l], height[r]) - height[cur]) * (r - l - 1); } stack.push(i); } return capacity;};