UVa 839 - Not so Mobile

#include <cstdio>
using namespace std;

struct Node
{
int lw, ld, rw, rd;
Node *left, *right;
Node()
{
left = right = 0;
}
};

Node *Build();
bool Judge(Node *root);

int main()
{
//freopen("input.txt", "r", stdin);
int T;
scanf("%d", &T);
while (T--)
{
Node *root;
root = Build();
bool result = Judge(root);
if (result)
printf("YES\n");
else
printf("NO\n");
if (T)
printf("\n");
}
return 0;
}

Node *Build()
{
Node *root = new Node();
scanf("%d%d%d%d", &root->lw, &root->ld, &root->rw, &root->rd);
if (root->lw == 0)      //如果左边的重量是0, 说明有左子树
{
root->left = Build();
root->lw += root->left->lw + root->left->rw;    //同时计算重量
}
if (root->rw == 0)      //同理
{
root->right = Build();
root->rw += root->right->lw + root->right->rw;
}
return root;
}

bool Judge(Node *root)
{
if (root)
if (root->lw * root->ld != root->rw * root->rd)
return false;
else if (!Judge(root->left) || !Judge(root->right))
return false;
return true;
}