[실2] 1182 - 부분수열의 합

#include <iostream>
#include <limits.h>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
#include <queue>	
#include <map>
#include <set>

using namespace std;
using ll = long long;

#pragma region 상하좌우 / 위치

const pair<int, int> dir[]
{
	{  1,  0 },
	{ -1,  0 },
	{  0, -1 },
	{  0,  1 },
};

#define _y first
#define _x second

#pragma endregion

#pragma region 빠른 입출력

#define FAST_IO() \
{\
	ios::sync_with_stdio(false);\
	cin.tie(NULL); \
	cout.tie(NULL); \
}\

#pragma endregion

vector<int> v;
int n, s, cnt;

void dfs(int idx = 0, int sum = 0)
{
	if (idx == n)
		return;

	int val = sum + v[idx];

	if (val == s)
		cnt++;

	dfs(idx + 1, sum);
	dfs(idx + 1, val);
}

int main()
{
	FAST_IO();
	cin >> n >> s;
	v.resize(n);

	for (int i = 0; i < n; i++)
		cin >> v[i];

	dfs();
	cout << cnt;
}