求助，样例都没过555

样例输出的是555，真的很神奇，废话少说，请看代码 ->

#include<bits/stdc++.h>
using namespace std;
int a[1000005],m,n,q,ans = 0;
int f(int q){
    int l = 0,r = n,mid;
    while(l<r){
        mid = (l+r)/2;
        if(a[mid] = q) return mid;
        else if(a[mid] < q) l = mid+1;
        else r = mid-1;
    }
    return -1;
}
int main(){
    scanf("%d %d",&n,&m);
    for(int i = 0; i < n; i++){
        scanf("%d",&a[i]);
    }
    for(int i = 1; i <= m; i++){
        scanf("%d",&q);
        ans = f(q);
        cout << ans << " ";
    }
    return 0;
}