二分法找数

#include<stdio.h>
#include<algorithm>
using namespace std;
int main()
{
    int a[10010];
    int n,k,i;
    scanf("%d%d",&n,&k);
    for(i=0;i<n;i++)
    {
        scanf("%d",&a[i]);
    }
    sort(a,a+n);
    int high,low,mid;
    high=n;
    low=0;
    while(high>=low)
    {
        mid=(high+low)/2;
        if(a[mid]>k)
            high=mid-1;
        if(a[mid]<k)
            low=mid+1;
        if(a[mid]==k)
        {
            printf("%d
",mid);
            return 0;
        }
    }
    printf("NO
");
    return 0;
}