[Algorithm - Recursive - Code] section and questions

Given integers a1, a2, ..., an. Some may judge whether to choose the number, and make them exactly k. (Programming Contest challenge from ch02p30)

 

 1 #include <iostream>
 2  
 3 bool dfs(int ,int ,int ,int,int[]);
 4 void solve(int,int,int[]);
 5 int main() {
 6     using namespace std;
 7  
 8     int num,sum=0;
 9     //输入输出
10     cin >> num;
11     int sta[num];
12     int b = 0 ;
 13 is      for ( int A = 0 ; A <NUM; A ++ ) {
 14          CIN >> B;
 15          STA [A] = B;
 16      }
 . 17   
18 is      int K;
 . 19      CIN >> K;
 20 is      // search 
21 is      Solve (NUM, K, STA);
 22 is      return  0 ;
 23 is  }
 24  // have been previous item i and the sum, then after branching to the item i 
25  BOOL DFS ( int i, int sum, int NUM,int K, int STA []) {
 26 is   
27      // first n entries have if the calculated, and whether the return is equal to k sum 
28      IF (I == NUM) return SUM == K;
 29   
30      // is not added a [i] in the case 
31 is      IF (DFS (I + . 1 , SUM, NUM, K, STA)) return  to true ;
 32   
33 is      // add a [i] in the case 
34 is      IF (DFS (I + . 1 , SUM + STA [ I], NUM, k, STA)) return  to true ;
 35   
36      // whether plus without a [i] k can not make up returns to false 
37 [      return  to false ;
 38 is }
39 void solve(int num, int k,int sta[]) {
40     if (dfs(0, 0, num ,k,sta)) printf("Yes\n");
41     else printf("No\n");

 

 c and c ++ mixed up with. . . In fact, the book is used is c and I will c ++.

 

Input example

4

1 2 4 7

13

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Yes