nyoj--1058 部分和问题(dfs)

题解

#include <iostream>
#include <vector>
#include <cstring>
#include <algorithm>
using namespace std;

const int maxn = 25;
int   a[maxn], vis[maxn];
int   n, k, flag;

void dfs(int pos, int sum)
{
if(sum > k) return;
if(sum == k){
if(flag) return;
flag = 1;
cout << "YES" << endl;
for(int i = 0; i < n; ++i)
if(vis[i]) cout << a[i] << " ";
cout << endl;
return;
}
for(int i = pos; i < n; ++i)
{
sum += a[i];
vis[i] = 1;
dfs(i + 1, sum);
sum -= a[i];
vis[i] = 0;
}
}

int main()
{
while(cin >> n >> k)
{
memset(vis, 0, sizeof(vis));
for(int i = 0; i < n; ++i) cin >> a[i];
flag = 0;
dfs(0, 0);
if(!flag) cout << "NO" << endl;
}

return 0;
}