算法：搜索

描述 One day,Tom’s girlfriend give him an array A which contains N integers and asked him:Can you choose some integers from the N integers and the sum of them is equal to K.

输入There are multiple test cases.

Each test case contains three lines.The first line is an integer N(1≤N≤20),represents the array contains N integers. The second line contains N integers,the ith integer represents A[i](-10^8≤A[i]≤10^8).The third line contains an integer K(-10^8≤K≤10^8).输出If Tom can choose some integers from the array and their them is K,printf ”Of course,I can!”; other printf ”Sorry,I can’t!”.样例输入4

1 2 4 7

13

4

1 2 4 7

15

样例输出

Of course,I can!

Sorry,I can't!

代码：

#include 
    
       #include 
     
        #include 
      
         #include 
       
          #include 
        
           using namespace std;  int n,m,a[25],flag;  int dfs(int i,int sum)  {    if(i==n)        return sum==m;    if(dfs(i+1,sum))        return 1;    if(dfs(i+1,sum+a[i]))        return 1;    return 0;  }   int main()   {   	  int i,j,k;   	  while(cin>>n)   	  {   	  	  for(i=0;i
         
          >a[i]; cin>>m; if(dfs(0,0)) cout<<"Of course,I can!"<