【算法笔记】快排（Java实现）

public class QuickSort {
public static void quickSort(int[] arr,int low,int high){
int i,j,temp,t;
if(low>high){
return;
}
i=low;
j=high;
//temp就是基准位
temp = arr[low];

    while (i<j) {
        //先看右边，依次往左递减
        while (temp<=arr[j]&&i<j) {
            j--;
        }
        //再看左边，依次往右递增
        while (temp>=arr[i]&&i<j) {
            i++;
        }
        //如果满足条件则交换
        if (i<j) {
            t = arr[j];
            arr[j] = arr[i];
            arr[i] = t;
        }

    }
    //最后将基准为与i和j相等位置的数字交换
     arr[low] = arr[i];
     arr[i] = temp;
    //递归调用左半数组
    quickSort(arr, low, j-1);
    //递归调用右半数组
    quickSort(arr, j+1, high);
}


public static void main(String[] args){
    int[] arr = {10,7,2,4,7,62,3,4,2,1,8,9,19};
    quickSort(arr, 0, arr.length-1);
    for (int i = 0; i < arr.length; i++) {
        System.out.println(arr[i]);
    }
}

}