UVA 112 Tree Summing二叉木

#include<iostream>
#include<cstdlib>
#include<stack>
using namespace std;

struct Node
{
	int value;
	Node *left,*right;
};

int I;
bool dfs(Node *n,int sum)
{
	sum+=n->value;
	if(!n->left&&!n->right&&sum==I) return 1;
	if(n->left&&dfs(n->left,sum)) return 1;
	if(n->right&&dfs(n->right,sum)) return 1;
	return 0;
}		
int main()
{
	//freopen("in.txt","r",stdin);
	int num;
	char c;
	stack<Node *> s_Node;
	while(cin>>I)
	{
		while(!s_Node.empty()) s_Node.pop();
		int left_num=0,right_num=0;//       
		do
		{
			cin>>c;
			if(c=='(')
			{
				if(!(cin>>num))//      ，   ')'
				{
					cin.clear();
					cin>>c;
					Node *tmp=NULL;
					s_Node.push(tmp);
				}
				else
				{
					left_num++;
					Node *tmp=(Node *)malloc(sizeof(Node));
					tmp->value=num;
					tmp->left=tmp->right=NULL;
					s_Node.push(tmp);
				}
			}
			else
			{
				right_num++;
				Node *tmp,*left,*right;
				right=s_Node.top();
				s_Node.pop();
				left=s_Node.top();
				s_Node.pop();
				tmp=s_Node.top();
				tmp->left=left;
				tmp->right=right;
			}
		}while(left_num>right_num);
		Node *root=s_Node.top();
		s_Node.pop();
		if(root)
		{
			if(dfs(root,0))
				cout<<"yes"<<endl;
			else
				cout<<"no"<<endl;
		}
		else
			cout<<"no"<<endl;
	}
	return 0;
}