poj1552

简单题

View Code

#include <iostream>

#include <cstdlib>

#include <cstdio>

#include <cstring>

using namespace std;



#define maxn 20



int n;

int f[maxn];



void input()

{

    n = 0;

    while (scanf("%d", &f[n]), f[n])

    {

        if (f[n] == -1)

            exit(0);

        n++;

    }

}



void work()

{

    int ans = 0;

    for (int i = 0; i < n; i++)

        for (int j = 0; j < n; j++)

            if (f[i] == f[j] * 2)

                ans++;

    printf("%d\n", ans);

}



int main()

{

    while (1)

    {

        input();

        work();

    }

}