UVA 839(p157)----Not so Mobile

#include<bits/stdc++.h>using namespace std;int flag;int solve(){    int w1,d1,w2,d2;    scanf("%d%d%d%d",&w1,&d1,&w2,&d2);    if(!w1) w1=solve();    if(!w2) w2=solve();    if(w1*d1!=w2*d2) flag=0;    return w1+w2;}int main(){    int t;    scanf("%d",&t);    while(t--)    {        flag=1;        solve();        if(flag) printf("YES\n");        else printf("NO\n");        if(t) printf("\n");    }    return 0;}

题目地址：https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=780