大一求助 哪个大佬帮我看看

#include<stdio.h>
int a[1000005];
int main() {
    int n, m, i, j, x, mid, l, r;
    scanf("%d%d\n", &n, &m);
    for (i = 1; i <= n; i++) {
        scanf("%d", &a[i]);
    }
    for (j = 1; j <= m; j++) {
        scanf("%d", &x);
        l=1,r=n;
        while (l<r) {
        mid = (l + r) / 2;
            if (x <=a[mid])
                r = mid;
            if (x >a[mid])
                l = mid + 1;
        }
        if (a[r]!= x)
            printf("-1");
        else
            printf("%d  ",r);
    }
    return 0;
}