数据结构实验之查找四：二分查找

#include <iostream>

#include <algorithm>

#include <cstdio>

using namespace std;

int a[10000000+5];

int n, m, key;

int fin(int i, int j) {

    if(i>j) return -1;

    int mid=(i+j)/2;

    if(a[mid]==key) return mid-1;

    if(a[mid]>key)

        return fin(i,mid-1);

    return fin(mid+1,j);

}

int main()  {

    while(~scanf("%d %d", &n, &m)) {

        for(int i=1;i<=n;i++)

            scanf("%d", &a[i]);

        while(m--) {

            scanf("%d", &key);

            printf("%d\n", fin(1,n));

        }

    }

    return 0;

}