1、翻转字符串算法挑战
function reverseString(str) {
var strarr = str.split("");
strarr = strarr.reverse();
str = strarr.join("");
return str;
}reverseString("hello");
2、阶乘算法挑战
function factorialize(num) {
if(num <= 1) return 1;return num*factorialize(num-1);
}factorialize(5);
3、回文算法挑战
function palindrome(str) {var str1 = str.toLowerCase(); var reg = /[\W\_]/g; var str2 = str1.replace(reg, "");var str3 = str2.split(""); var str4 = str3.reverse(); var str5 = str4.join(""); return str2 === str5;
}
palindrome("eye");
4、寻找最长的单词算法挑战
function findLongestWord(str) {var arr = str.split(" ");//空格为界限拆分字符串为数组["The","quick","brown","fox","jumped","over","the","lazy","dog"]arr.sort(function compare(x,y){ //用sort()方法对数组进行排序return y.length-x.length;//（按数组每项{即单词长度}降序排序）});
return arr[0].length;//取第一项为单词长度最长一项
}findLongestWord("The quick brown fox jumped over the lazy dog");
5、设置首字母大写算法挑战
function titleCase(str) {
//把字符串所有的字母变为小写，并根据空格转换成字符数组
var arr = str.toLowerCase().split(" ");
//遍历字符数组
for(var i = 0;i < arr.length;i++){//把第一个字符变为大写arr[i] = arr[i][0].toUpperCase() + arr[i].substring(1,arr[i].length);
}
//加上空格，返回原模式的字符串
return arr.join(" ");}titleCase("I'm a little tea pot");
6、寻找数组中的最大值算法挑战
function largestOfFour(arr) {
var maxArr = [];
//遍历数组
for(var i = 0;i < arr.length;i++){for(var j = 0;j < arr[i].length;j++){//先把第一个数赋值给对应的最大数组maxArr中，用arr[i]中后面的数和它比较，若比它小则不变，否则替换。if(j == 0){maxArr[i] = arr[i][j]; }else{maxArr[i] = arr[i][j] > maxArr[i]?arr[i][j]:maxArr[i]; }}
}
return maxArr;
}largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);
7、确认末尾字符算法挑战
function confirmEnding(str, target) {return str.endsWith(target);
}confirmEnding("Bastian", "n");
8、重复操作算法挑战
function repeat(str, num) {
// repeat after me
if(num==0){return "";
}else{var string="";for (var i = 0; i <num; i++) {string=string+str;}
}
return string;
}repeat("abc", 3);
9、字符串截取算法挑战
function truncate(str, num) {
// Clear out that junk in your trunkif(str.length <= num){return str; //给定参数大于字符串长度，返回字符串本身}else if(str.length > num && num <= 3){//三个点号不计入字符串长度return str.slice(0, num) + "...";}else if(str.length > num && num > 3){//三个点号计入字符串长度return str.slice(0, num - 3) + "...";//用slice()方法将后三个字符去掉}return str; }truncate("A-tisket a-tasket A green and yellow basket", 11);
10、数组分割算法挑战
function chunk(arr, size) {var rsArr = [];for(var i=0;i<arr.length;i+=size){var tempArr=[];for(var j=0;j<size&&i+j<arr.length;j++){tempArr.push(arr[i+j]);}rsArr.push(tempArr);}return rsArr;
}chunk(["a", "b", "c", "d"], 2);
11、数组截断算法挑战
function slasher(arr, howMany) {
var newArr = [];
if(arr.length - howMany > 0){for(var i = howMany;i < arr.length; i++){newArr.push(arr[i]);}
}
return newArr;}slasher([1, 2, 3], 2);
12、数组查询算法挑战
function mutation(arr) {str1 = arr[0].toLowerCase();str2 = arr[1].toLowerCase();for (var i = 0; i < str2.length; i++) {if (str1.indexOf(str2[i]) < 0) {return false;}}return true;
}
mutation(["hello", "hey"]);
13、删除数组中特定值算法挑战
function bouncer(arr) {var newArr = [];for(var i = 0; i < arr.length; i++){if(!(!arr[i] || arr[i] === "")){newArr.push(arr[i]);}}return newArr;}bouncer([7, "ate", "", false, 9]);
14、去除数组中任意多个值算法挑战
function destroyer(arr) {var argArr = arguments;for (var i = 1; i < argArr.length; i++) {arr = arr.filter(function(val) {return argArr[i] !== val;});}return arr;
}destroyer([1, 2, 3, 1, 2, 3], 2, 3);
15、数组排序并插入值算法挑战
function where(arr, num) {//把参数放进数组arr.push(num);//对数组进行升序排序arr.sort(function(x,y){return x - y;});//返回参数在数组中的位置return arr.indexOf(num);
} where([40, 60], 50);
16、位移密码算法挑战
function rot13(str) { // LBH QVQ VG!
var n=0;
var num=0;
var arr=new Array();
for (var i = 0; i < str.length; i++) {n=str.charCodeAt(i);if(n>=65&&n<=90){if(n>=78&&n<=90){num=n-13;arr[i]=String.fromCharCode(num);}else{num=(90-(13-n+65)+1);arr[i]=String.fromCharCode(num);}}else{arr[i]=String.fromCharCode(n);}
}
var string=arr.join("");
return string;}
// Change the inputs below to test
rot13("SERR PBQR PNZC");