(DS1.4.)poj 1552 Doubles(测试组数和每组测试用例的个数不定)

#include <iostream>
#include <cstdio>

using namespace std;
const int maxn  = 20;
int main(){
	int a[maxn];
	cin >> a[0];
	while(a[0] != - 1){
		int i = 1,j,count = 0;

		for(; ; i++){
			scanf("%d",&a[i]);

			if(a[i] == 0){
				break;
			}
		}
		int n = i;
		for(i = 0 ; i < n - 1 ; ++i){
			for(j = i + 1 ; j < n ;++j ){
				if(a[i]*2 == a[j] || a[j]*2 == a[i]){
					count++;
				}
			}
		}

		printf("%d\n",count);
		cin >> a[0];
	}
	
	return 0;
	

}

Doubles