hiho1128 非有序数组的二分查找 (快速排序)

链接：

hihocoder1128

代码：

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int a[1000050];
int _sort(int left,int right)
{
    int x=a[left];
    while(left<right)
    {
        while(a[right]>x&&left<right)
            right--;
        if(left<right)
        {
            a[left]=a[right];
            left++;
        }
        while(a[left]<x&&left<right)
            left++;
        if(left<right)
        {
            a[right]=a[left];
            right--;
        }
    }
    a[left]=x;               //left==right
    return left;
}

int unsorted_binarysearch(int left,int right,int key)   //每次都选择起点作为“枢纽”
{
    if(left>right)
        return -1;

    int x=a[left];
    int mid_loc=_sort(left,right);

    if(x==key)
        return mid_loc;
    else if(x>key)
        unsorted_binarysearch(left,mid_loc-1,key);
    else
        unsorted_binarysearch(mid_loc+1,right,key);

}

int main()
{
//    freopen("in.txt","r",stdin);
    int n,k;
    scanf("%d%d",&n,&k);
    for(int i=1; i<=n; i++)
        scanf("%d",&a[i]);
    cout<<unsorted_binarysearch(1,n,k)<<endl;
    return 0;
}