今日整理的简单6个题目，JavaScript算法题目，作为日常算法练手用。
1、求2数之和
从给定数组之中寻找和为目标数字的指定位置
// 求2数之和 const sumTwo = (arr, target) => { for (let i = 0; i < arr.length; i++) { for (let j = i + 1; j <= arr.length; j++) { if (arr[i] + arr[j] === target) { return [i, j] } } } return [] } console.log('sumTwo', sumTwo([1, 3, 5, 8], 8)) const sumTwo2 = (arr, target) => { const map = new Map() for (let i = 0; i < arr.length; i++) { const complement = target - arr[i] if (map.has(complement)) { return [map.get(complement), i] } map.set(arr[i], i) } return [] } console.log('sumTwo2', sumTwo2([1, 3, 5, 8], 9))2、替换空格
替换空格: 实现一个函数，将一个字符串中的空格替换成“%20”或者指定字符
const replaceStr = (str,text = '%20') => { return str.split(' ').join(text) } console.log('replaceStr', replaceStr('hello world, a good nice day')) const replaceStr2 = (str) => { let newStr = '' for (let item of str) { if (item == ' ') { newStr += text } else { newStr += item } } return newStr }3、斐波那契数列
实现类似累加功能，不大于50
// 斐波那契数列 function fbnq (n) { if (n <= 1) { return 1 } return fbnq(n - 1) + fbnq(n - 2) } //推荐方式 function fbnq2(n) { if (n <= 1) return n let a = 0, b = 1 for (let i = 2; i <= n; i++) { [a, b] = [b, a + b] // ES6解构赋值 } return b } console.log(fbnq2(10)) // 554、返回数字
返回给定字符串内的数字，非数字返回0
// 返回数字 function getNumber (str) { let newStr = '' for (let item of str) { if (Number(item)) { newStr += item } else { newStr += '0' } } return newStr } console.log('getNumber', getNumber('+2147#48^3647'));5、返回重复的字母次数
// 返回重复的字母次数 function getRepeat (str) { let map = new Map() for (let item of str) { if (!map.has(item)) { map.set(item, 1) } else { map.set(item, map.get(item) + 1) } } return map } console.log('getRepeat', getRepeat('afdfadfdfdfdfdqqqqqqqqqqqqqq'));6、返回最长单词
// 返回最长单词 function findLongestWord (str) { const words = str.replace(/[^ws]/g, '').split(/s+/) let longestWord = '' let maxLength = 0 for (let word of words) { if (word.length > maxLength) { maxLength = word.length longestWord = word } } return { longestWord, length: maxLength } } console.log(findLongestWord("JavaScript and TypeScript are great"))