样例没问题啊 全文RA了 求助

#include<iostream>
#include<cstdio>
using namespace std;
const int N=100100;
int a[N];
int n,m,x;
int binary_search(int x){
    int l=0,r=n+1;
    int mid;
    while(l+1!=r){
        mid=(l+r)/2;
        if(a[mid]<x)    l=mid;
        else    r=mid;
    }
    return a[r]==x ?r : -1;
}
int main(){
    scanf("%d %d",&n,&m);
    for(int i=1;i<=n;i++)   scanf("%d",&a[i]);
    while(m--){
        scanf("%d",&x);
        printf("%d ",binary_search(x));
    }
    return 0;
}