qq_44805237的博客

6；

function Foo(){}Foo.prototype = {value:"bar"}let foo = new Foo();console.log(foo.constructor)function removeDuplications(nums){ for(let i = 0; i < nums.length-1; i++){ if(nums[i] === nums[i+1]){ nums.splice(i,1); i--;...

function getRow(rowIndex){ if(rowIndex == 0) return [1]; let list = [1]; for(let i = 0; i < rowIndex; i++){ list.unshift(0); for(let j = 0; j < i+1; j++){ list[j] = list[j] + list[j+1]; } } return lis...

var missingNumber = function(nums) { nums.sort((a,b) => a-b); let len = nums.length; let arr = []; for(let i = 0; i <= len; i++){ arr[i] = i; } arr = arr.filter(el => !nums.includes(el)) return arr[0];};...

function kidsWithCandies(candies, extraCandies){ let max = Math.max(...candies); for(let i = 0; i < candies.length; i++){ if(candies[i]+extraCandies >= max){ candies[i] = true; }else{ candies[i] = false; }...

5

随机函数

1.2.(1)最后两者de 大小，取决于n。(2)map的标准写法，只能用for of循环；使用for in会报错。map只能用for of 遍历var leastInterval = function(tasks, n) { let map = new Map(), len = tasks.length, max = 0, maxcount = 1; for(let i = 0; i < len; i++){ ..

B

let time1 = '2019-02-14 21:00:00';let time2 = '2019-05-01 09:00:00';console.log(time1 > time2);console.log(time1 < time2);

function remove2(arr, target){ "use strict" return arr.filter(function (item){ return item !== target; }) console.log(arr) } remove2(arr, '教')

1.2.3.数字和下划线不影响str.toLowerCase();

var num = 3; var value = parseInt(num).toString(2);

var summaryRanges = function(arr) { let len = arr.length; let arr1 = []; let i = 0; while(i < len){ let a = arr[i]; let b = ''; let flag = false; while(arr[i] + 1 == arr[i + 1]){ i++; ...

res：Bres：A

let a = { n: 1 };let b = a;a.m = a = {m: 2};console.log(a);console.log(b);

function CheckPermutation(s1, s2){ s1 = s1.split(''); s2 = s2.split(''); s1.sort(); s2.sort(); if(s1.length != s2.length) return false; let len = s1.length; for(let i = 0; i < len; i++){ if(s1[i] != s2[i]) return false; }...

function numSmallerByFrequency(queries, words){ function countNum(arr){ for(let i = 0; i < arr.length; i++){ let a = arr[i].split(''); let count = 0; a.sort(); for(let j = 0; j < a.length; j++){ ...

1.2.***初始化map需要一个二维数组；var beautySum = function(s) { let len = s.length, sum = 0, subStr = ''; for(let i = 3; i <= len; i++){ for(let j = 0; j <= len-i; j++){ subStr = s.slice(j,j+i); let map = new Map(..

function getRow(rowIndex){ if(rowIndex == 0) return []; let list = [1]; let res = []; res[0] = [1]; for(let i = 0; i < rowIndex-1; i++){ list.unshift(0); for(let j = 0; j < i+1; j++){ list[j] = list[j] + list[j+1]...

function sumOldLengthSubarrays(arr){ var len = arr.length; var sum = 0; for (var i = 0; i < len; i = i + 2){ var from = 0; while(from + i < len){ for(var j = from; j < from + i...

function mostVisited(n, rounds){ let arr = Array(n+1).fill(0); let answer = []; let len = rounds.length; for(let i = 0; i < len-1; i++){ if(rounds[i] < rounds[i+1]){ for(let j = rounds[i]; j < rounds[i+1]; j++){ ...

（1）原型链肯定有顶端（基础对象），顶端对象肯定没有原型（2）Object.creat(null), 这时候就没有原型了

A

1.中心扩展2.dp（1）因为状态转移方程是dp[i, j] = dp[i+1, j-1] + s[i] === s[j]；所以循环先从尾部开始。

三种：function specialArray(nums){ let len = nums.length; let = count = 0; for(let i = 0; i <= len; i++){ for(let j = 0; j < len; j++){ if(nums[j] >= i){ count++; } } ...

var isUnique = function(astr) { a = astr.split('').sort(); for(let i = 0; i < a.length; i++){ if(a[i] = a[i+1]) return false; } return true;};

2.221.当key值为对象时候，系统会自动将字符串转为[object Object]2.23

1.24面向对象按照顺序执行即可，new b 的时候，A的prototype里面只有 n = 1;1.25 // 1 之后有空格就不会报错1.26五：先进行隐式的强制类型转换：Number(A)和Number(B)的结果都是NaN，最终结果是字符串‘NaN2’六：NaN + 2 => NaN : NaN数字运算结果都是NaN...

1.数组所有方法2.没有对原数组进行修改的方法：

function sumEventAfterQueries(A, queries){ let len = A.length; let sum = 0; let answer = []; function evenSum(A){ for(let i = 0; i < len; i++){ if(A[i] % 2 == 0){ sum += A[i]; } } return sum; } fo...

var findShortestSubArray = function(nums) { let len = nums.length; let count = 1; let max = 1; let minSub = 1; for(let i = 0; i < len; i++){ for(let j = i+1; j < len; j++){ if(nums[i] == nums[j]){ ...

function addToArrayFrom(A, K){ let a = BigInt(A.join('')); a += BigInt(K); a = a.toString(); a = a.split(''); for(let i = 0; i < a.length; i++){ a[i] = Number(a[i]); }return a;}let A = [1,2,6,3,0,7,1,7,1,9,7,5,6,6,4,4,...

function countGoodTriplets(arr, a, b, c){ var i, j, k, count = 0; if(arr.length < 3){ count = 0; }else{ for(i=0; i<arr.length-2; i++){ for(j=i+1; j<arr.length - 1; j++){ ...

var a = 1;a = (++a, a++);console.log(a);a = (a++, ++a);console.log(a);

function replaceElements(arr){ let len = arr.length; let max = 0; for(let i = 0; i < len-1; i++){ for(let j = i+1; j < len; j++){ max = max > arr[j] ? max : arr[j]; } arr[i] = max; max = 0; } arr[len-1...

function fib(n){ if(n == 0){ return 0; } if(n == 1 || n == 2){ return 1; } return fib(n -2) + fib(n - 1);}function fib1(n){ if(n == 0){ return 0; } if(n == 1 || n == 2){ return 1; ...

（1） 暴力解法：但是适合不知井字棋，更大也可以 let A = []; let B = []; let isAWin = false let isBWin = false let len = moves.length for (let i = 0; i < len; i++) { if (i % 2 == 0) { A.push(moves[..

var shiftGrid = function(grid, k) { let len0 = grid.length; let len1 = grid[0].length; var arr = []; var c = 0; for(let i = 0; i < len0; i++){ for(let j = 0; j < len1; j++){ arr[c] = grid[i][j]; ...