HDU2266How Many Equations Can You Find(深搜)

How Many Equations Can You Find

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

Total Submission(s): 641    Accepted Submission(s): 421

Problem Description

Now give you an string which only contains 0, 1 ,2 ,3 ,4 ,5 ,6 ,7 ,8 ,9.You are asked to add the sign ‘+’ or ’-’ between the characters. Just like give you a string “12345”, you can work out a string “123+4-5”. Now give you an integer N, please tell me how many ways can you find to make the result of the string equal to N .You can only choose at most one sign between two adjacent characters.

 

Input

Each case contains a string s and a number N . You may be sure the length of the string will not exceed 12 and the absolute value of N will not exceed 999999999999.

 

Output

The output contains one line for each data set : the number of ways you can find to make the equation.

 

Sample Input

123456789 321 1

 

Sample Output

181

 

#include <stdio.h>  #include <string.h>   #define ll long long  int len;  char s[15];  ll n,ans;    void dfs(int sum,int id)  {      if(id==len)      {          if(sum==n)              ans++;          return;      }      ll tmp=0;      for(int i=id;i<len;i++)      {          tmp=tmp*10+(s[i]-'0');          dfs(sum+tmp,i+1);          if(id)              dfs(sum-tmp,i+1);      }  }  int main()  {     while(~scanf("%s%lld",s,&n))     {         ans=0;         len=strlen(s);         dfs(0,0);         printf("%lld\n",ans);     }  }