PAT甲级1002水题飘过

#include<iostream>
#include<string.h>
using namespace std;

double a[1005];

int main(){
    int n1, n2;
    while(scanf("%d", &n1) != EOF){
        memset(a, 0, sizeof(a));
        for(int i = 1; i <= n1; i++){
            int x;
            double y;
            scanf("%d%lf", &x, &y);
            a[x] += y;
        }
        scanf("%d", &n2);
        for(int i = 1; i <= n2; i++){
            int x;
            double y;
            scanf("%d%lf", &x, &y);
            a[x] += y;
        }
        int cnt = 0;
        for(int i = 0; i <= 1000; i++){
            if(a[i] != 0) cnt++; 
        }
        printf("%d", cnt);
        for(int i = 1000; i >= 0; i--){
            if(a[i] != 0){
                printf(" %d %.1lf", i, a[i]);
            }
        }
        printf("\n");
    }
    return 0;
}