poj 1145 二叉树和为某一值的情况

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <vector>
#include <stack>
#include <deque>
#include <queue>
#include <bitset>
#include <list>
#include <map>
#include <set>
#include <iterator>
#include <algorithm>
#include <functional>
#include <utility>
#include <sstream>
#include <climits>
#include <cassert>
#define MID(x,y) ( ( x + y ) >> 1 )
#define L(x) ( x << 1 )
#define R(x) ( x << 1 | 1 )
#define BUG puts("here!!!");
#define STOP system("pause");

using namespace std;
struct Node {
	int value;
	Node* lchild;
	Node* rchild;
};
bool flag;
Node* create() {
	char ch;
	int v;
	while(scanf("%c", &ch) && (ch == '(' || ch == ' ' || ch == '\n'));
	if(ch == ')') return NULL;
	cin.putback(ch);
	scanf("%d", &v);
	Node* root = new Node();
	root->value = v;
	root->lchild = create();
	root->rchild = create();
	while(scanf("%c", &ch) && ch != ')');
	return root;
}
void inOrder(Node* root) {
	if(root == NULL) return;
	printf("%d ", root->value);
	if(root->lchild) inOrder(root->lchild);
	if(root->rchild) inOrder(root->rchild);
}
void findPath(Node* pr, int exSum,  int curSum) {
	curSum += pr->value;
	if(curSum == exSum && pr->lchild == NULL && pr->rchild == NULL) {
		flag = true;
		return;
	}
	if(!flag && pr->lchild != NULL) {
		findPath(pr->lchild, exSum, curSum);
	}
	if(!flag && pr->rchild != NULL) {
		findPath(pr->rchild, exSum, curSum);
	}
	if(!flag) curSum -= pr->value;
}
void solve(Node* root, int exSum) {
	if(root == NULL) {
		flag = false;
		return;
	}
	int curSum = 0;
	findPath(root, exSum, curSum);
}
int main() {
	int tar;
	while(scanf("%d", &tar) != EOF) {
		flag = false;
		Node* root = create();
		solve(root, tar);
		if(flag) printf("yes\n");
		else printf("no\n");
	}
	return 0;
}