部分源码==》https://github.com/calamus0427/commonJS
翻转字符串算法挑战
function reverseString(str) {
str = str.split("").reverse().join("")
return str;
}
reverseString("hello");
阶乘算法挑战
function factorialize(num) {
let sum = num ;
if(num == 0){
return 1 ;
}else{
while(num > 1 ){
sum *= (num-1) ;
num -- ;
}
}
return sum;
}
factorialize(0);
回文算法挑战
function palindrome(str) {
str = str.replace(/[^a-zA-Z\d]/g, "");
return str.toLowerCase() == str
.split("")
.reverse()
.join("")
.toLowerCase();
}
palindrome("0_0 (: /-\ :) 0-0");
寻找最长的单词算法挑战
function findLongestWord(str) {
str = str.split(" ");
let len = str[0].length ;
for(let i = 0 ; i < str.length ; i++){
if(len <= str[i].length){
len = str[i].length ;
}
}
return len;
}
findLongestWord("The quick brown fox jumped over the lazy dog");
设置首字母大写算法挑战
function titleCase(str) {
str = str.split(" ");
for(let i = 0 ; i < str.length ; i++){
str[i] =str[i].substring(0, 1).toUpperCase() + str[i].substring(1).toLowerCase();
}
str = str.join(" ");
return str;
}
titleCase("sHoRt AnD sToUt");
寻找数组中的最大值算法挑战
function largestOfFour(arr) {
let newArr = [] ;
for(let i = 0 ; i < arr.length ; i ++){
let max = arr[i][0];
for(let j = 0 ; j < arr[i].length ; j++){
if(max <= arr[i][j]){
max = arr[i][j];
}
}
newArr.push(max);
}
return newArr;
}
largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);
确认末尾字符算法挑战
function confirmEnding(str, target) {
// "Never give up and good luck will find you."
// -- Falcor
console.log(str,"|||",str.substring(str.length-target.length))
// return str.substring(str.length-target.length) == target;
return str.endsWith(target);
}
confirmEnding("Bastian", "n");
重复操作算法挑战
function repeat(str, num) {
// repeat after me
if(num < 0){
return ""
}else{
let newStr = "" ;
for(let i = 0 ; i < num ; i++){
newStr += str ;
}
return newStr;
}
}
repeat("abc", 3);
字符串截取算法挑战
function truncate(str, num) {
// Clear out that junk in your trunk
if(str.length <= num ){
return str;
}else{
if(num <=3 ){
return str.substring(0,num)+"...";
} else{
return str.substring(0,num-3)+"...";
}
}
}
truncate("Peter Piper picked a peck of pickled peppers", 14);
数组分割算法挑战
function chunk(arr, size) {
// Break it up.
var index = 0;
var newArray = [];
while(index < arr.length) {
newArray.push(arr.slice(index, index += size));
}
return newArray;
}
chunk(["a", "b", "c", "d"], 2);
数组截断算法挑战
function slasher(arr, howMany) {
// it doesn't always pay to be first
return arr.slice(howMany);
}
slasher([1, 2, 3], 2);
数组查询算法挑战
function mutation(arr) {
let first = arr[0].toLowerCase();
let target = arr[1].toLowerCase().split("") ;
for(let i = 0 ; i < target.length ; i++){
if(first.indexOf(target[i]) < 0 ){
return false ;
}
}
return true ;
}
mutation(["zyxwvutsrqponmlkjihgfedcba", "qrstu"]);
删除数组中特定值算法挑战
function bouncer(arr) {
// Don't show a false ID to this bouncer.
return arr.filter(params => Boolean(params));
}
function isBad(params){
var result = Boolean(params);
return result;
}
bouncer([7, "ate", "", false, 9]);
去除数组中任意多个值算法挑战
function destroyer(arr) {
var args = [];
for(var i = 1; i < arguments.length; i++){ //将待摧毁的值放入一个数组中，赋值给变量args
args.push(arguments[i]);
}
var newArr=arr.filter(function(item){ //两个数组去重；
return args.indexOf(item) === -1;
});
return newArr;
}
destroyer([1, 2, 3, 1, 2, 3], 2, 3);
数组排序并插入值算法挑战
function where(arr, num) {
// Find my place in this sorted array.
arr.push(num);
arr = arr.sort(function(x,y){ //将num扔进arr中之后排序；
return x-y;
});
console.log(arr);
return arr.indexOf(num);
}
where([3, 10, 5], 3);
位移密码算法挑战
function rot13(str) { // LBH QVQ VG!
var newArr=[];
for(var i=0;i<str.length;i++){
var numbers=str.charCodeAt(i); //使用charCodeAt()方法取得每个字符的Unicode值，并保存在变量numbers中；
if(numbers<65||numbers>90){
newArr.push(String.fromCharCode(numbers));
}else if(numbers>77){
newArr.push(String.fromCharCode(numbers-13));
}else{
newArr.push(String.fromCharCode(numbers+13));
}
} //大写A-Z字母对应的Unicode值为65-90；通过判断，利用fromCharCode()将Unicode值又转换为字符；
return newArr.join("");
}
// Change the inputs below to test
rot13("SERR PBQR PNZC");