第37篇

1、手写数组快速排序

 1 var quickSort = function (arr) {
 2   if (arr.length <= 1) {
 3     return arr;
 4   }
 5 
 6   var pivotIndex = Math.floor(arr.length / 2);
 7   var pivot = arr.splice(pivotIndex, 1)[0];
 8   var left = [];
 9   var right = [];
10   for (var i = 0; i < arr.length; i++) {
11     if (arr[i] < pivot) {
12       left.push(arr[i]);
13     } else {
14       right.push(arr[i]);
15     }
16   }
17 
18   return quickSort(left).concat([pivot], quickSort(right));
19 }

2、判断一个字符串中出现次数最多的字符，并统计次数

 1 var str = "shdshdfjkfjfdgjkjdksgjskdjfsfsfsfjksjkfdkjf";
 2 var arr = str.split("").sort(); //把字符串变为数组，在排序
 3 str = arr.join("");
 4 var count = 0;
 5 var char = 0;
 6 var reg = /(w)1+/g;
 7 
 8 str.replace(reg, function (parent, son) {
 9   if (parent.length > count) {
10     count = parent.length;
11     char = son;
12   }
13 });
14 
15 console.log("最多的字符为：" + char + ";个数为：" + count);