算法笔记

给定n个数，以及数k，判断是否能够从n个数中找出任意个数，使其和等于k

 1 #include<iostream>
 2 #include<malloc.h>
 3 using namespace std;
 4 int sum_out;
 5 int *a;
 6 int max;
 7 bool dfs(int i,int sum){
 8
 9
10
11     if (i == max) return sum == sum_out;
12
13     if (dfs(i + 1, sum))return true;
14
15
16     if (dfs(i + 1, sum + a[i])) return true;
17
18     return false;
19
20
21
22 }
23 int main(){
24     cout << "max=";
25     cin >> max;
26     cout << endl;
27     cout << "sum=";
28     cin >> sum_out;
29     cout << endl;
30     a = (int *)malloc(sizeof(int)*max);
31
32     for (int i = 0; i < max; i++){
33         cin >> a[i];
34     }
35
36     if (dfs(0, 0)) printf("yes\n");
37     else
38         printf("no\n");
39     free(a);
40     system("PAUSE");
41     return 0;
42 }