poj 1145 Tree Summing

#include<iostream>#include<cstdio>#include<cstring>using namespace std;bool flag=false;int kk;char GetNext()  //将没用的符号过滤掉{    char c;    while(scanf("%c",&c) && (c==' ' || c=='n' || c==9 || c==10));    return c;}int dfs(int sum,int hight){    int sign=1,k=0,k1,k2;    char c;    c=GetNext();      if(c==')')    {        return hight;    }    if(c=='-')//当为负数时    {        sign=-sign;        c=GetNext();    }    while((c>='0' && c<='9'))//取数字    {        k=k*10+(c-'0')*sign;        scanf("%c",&c);    }    if(c=='n' || c==' ') c=GetNext();    if(c=='(') k1=dfs(sum+k,hight+1); //返回左孩子高度    c=GetNext();    if(c=='(') k2=dfs(sum+k,hight+1);//返回右孩子高度    c=GetNext();    if(k2==hight+1 && k1==hight+1)//判断是否是叶子节点    {        if(sum+k==kk) flag=true;    }    return 0;}int main(){    while(scanf("%d",&kk)!=EOF)    {        flag=false;        GetNext();        dfs(0,0);        //GetNext();        if(flag) printf("yesn");        else printf("non");    }    return 0;}