UVA - 112 Tree Summing

题目大意：给一个数和一棵树问是否有一叶子到根的值为该数。

解题思路：递归，若当前节点无孩子（叶子）则判断和是否为所需数字。结束后需将尾部反括号读入以免影响下一个样例。

#include<iostream>#include<cstdio>#include<cstdlib>#include<cstring>#include<cmath>#include<ctype.h>using namespace std;int n;void read() {    char c;    c = getchar();    while (c != '(' && c != ')')        c = getchar();}int dfs(int tot, int *leaf) {    int tmp, tag = 0, l = 0, r = 0;    read();    if (scanf("%d", &tmp)) {        *leaf = 1;        tot += tmp;        if (dfs(tot, &l)) tag = 1;        if (dfs(tot, &r)) tag = 1;        if (!l && !r)             if (n == tot) tag = 1;            else tag = 0;    }    read();    return tag;}int main() {    while (scanf("%d", &n) != EOF) {        int t = 1;        if (dfs(0, &t)) printf("yes\n");        else printf("no\n");    }return 0;}