839 - Not so Mobile

#include <stdio.h>int compute(){int wl,dl,wr,dr;scanf("%d%d%d%d",&wl,&dl,&wr,&dr);if(wl==0)wl=compute();if(wr==0)wr=compute();if(wl ==-1 || wr ==-1 || wl*dl!=wr*dr)return -1;return wl+wr;}int main(){int n;scanf("%d",&n);for(int i=0;i<n;i++){int result=compute();if(result==-1)printf("NO\n");elseprintf("YES\n");if(i<n-1)printf("\n");}return 0;}

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=104&page=show_problem&problem=780