UVA839 – Not so Mobile

題意：距離*重量，要使整個天平各個節點左右相等

思路：利用遞迴，從最底層判斷是否相等

#include<stdio.h>int flag;int dfs() {int wl, dl, wr, dr;scanf("%d %d %d %d", &wl, &dl, &wr, &dr);if (wl == 0)wl = dfs();if (wr == 0)wr = dfs();if (wl * dl == wr * dr) return wl + wr;elsereturn flag = 0;}int main() {int cas;scanf("%d", &cas);while (cas--) {flag = 1;dfs();if (flag)printf("YES\n");elseprintf("NO\n");if (cas)printf("\n");}return 0;}