Detailed explanation of javascript quick sort algorithm_javascript skills

The idea of ​​"quick sort" is very simple. The entire sorting process only requires three steps:

(1) Find a reference point in the data set

(2) Create two arrays to store the left and right arrays respectively

(3) Use recursion for the next comparison

Watch a demo: http://jsdo.it/norahiko/oxIy/fullscreen (The webpage may be slow to open, please wait)

<script type="text/javascript"> 

function quickSort(arr){
  if(arr.length<=1){
    return arr;//如果数组只有一个数，就直接返回；
  }

  var num = Math.floor(arr.length/2);//找到中间数的索引值，如果是浮点数，则向下取整
  var numValue = arr.splice(num,1);//找到中间数的值
  var left = [];
  var right = [];

  for(var i=0;i<arr.length;i++){
    if(arr[i]<numValue){
      left.push(arr[i]);//基准点的左边的数传到左边数组
    }
    else{
      right.push(arr[i]);//基准点的右边的数传到右边数组
    }
  }
 return quickSort(left).concat([numValue],quickSort(right));//递归不断重复比较
}
alert(quickSort([32,45,37,16,2,87]));//弹出“2,16,32,37,45,87”

</script>