快速排序

标签：数据结构 javascript快速排序

快速排序（js实现）

function Quicksort(a) {
        Qsort(a, 0, a.length - 1);
        return   a;
    }

    function Qsort(a, low, high) {
        var pivot;
        if (low < high) {
            pivot = Partition(a, low, high);
            Qsort(a, low, pivot - 1);
            Qsort(a, pivot+1, high);
        }


    }

   
    function Partition(a, low, high) {

        var temp;
        var pivotKey;
        pivotKey = a[low];
        while (low < high) {
            while (low < high && a[high] >= pivotKey)
                high--;
            temp = a[high];
            a[high] = a[low];
            a[low] = temp;
            while (low < high && a[low] <= pivotKey)
                low++;
            temp = a[low];
            a[low] = a[high];
            a[high] = temp;

        }
        return low;
    }

 function getRandom() {
        var count = 15;
        var random;
        var a = new Array();
        while (count--) {
            random = Math.floor(Math.random() * 1000);
            a.push(random);


        }
       
        return a;
    }

快速排序的算法思想最好还是看看数据结构的相关书籍吧，我这里只是简单的说下。快速排序就是冒泡排序的升级版本，实现思想就是预先设置一个所谓的中间量（piovtkey）,从low和height两个方向往中间走，完成把比piovtkey大的放右边，小的放左边。

 function Partition(a, low, high) {

        var temp;
        var pivotKey;
        pivotKey = a[low];
        while (low < high) {
            while (low < high && a[high] >= pivotKey)
                high--;
            temp = a[high];
            a[high] = a[low];
            a[low] = temp;
            while (low < high && a[low] <= pivotKey)
                low++;
            temp = a[low];
            a[low] = a[high];
            a[high] = temp;

        }
        return low;
    }

然后在递归调用.

if (low < high) {
            pivot = Partition(a, low, high);
            Qsort(a, low, pivot - 1);
            Qsort(a, pivot+1, high);
        }

快速排序

标签：数据结构 javascript快速排序

原文地址：http://blog.csdn.net/u014209090/article/details/45013569