POj 1145

伤不起呀

#include <stdio.h>int n;int flag;char inputFilter(){char c;while(scanf("%c",&c)&&c==' '||c=='\n'||c==9||c==10);return c;}int dfs(int sum,int height){      char c;   int sign=1;   int count=0;   c=inputFilter();//个人认为此处是本题的关键点1   if(c==')') return height;   if(c=='-')   {   sign=-1;   c=inputFilter();   }   while(c>='0'&&c<='9')   {   count=count*10+sign*(c-'0');   scanf("%c",&c);   }   if(c=='\n'||c==' ') c=inputFilter();   int k1=dfs(sum+count,height+1);   c=inputFilter();   int k2=dfs(sum+count,height+1);   c=inputFilter();   if(k1==height+1&&k2==height+1)//关键点2，判断终结点   {      if(sum+count==n) flag=1;   }   return 0;}int main(){while(scanf("%d",&n)!=EOF){flag=0;inputFilter();//使dfs第4 行的C读的是（后面的字符dfs(0,0);if(flag==1) printf("yes\n");else printf("no\n");}return 0;}