Submission #855251

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define FOR(i,k,n) for(int i = (int)(k); i < (int)(n); i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(a) a.begin(), a.end()
#define MS(m,v) memset(m,v,sizeof(m))
#define D10 fixed<<setprecision(10)
typedef long long ll;
typedef long double ld;
typedef vector<ll> vi;
typedef vector<string> vs;
typedef pair<int, int> pii;
const int MOD = 1000000007;
const int INF = MOD + 1;
const ld EPS = 1e-12;
template<class T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template<class T> T &chmax(T &a, const T &b) { return a = max(a, b); }

/*--------------------template--------------------*/
ll n, a, dp[55][55][2555];
vi x;

ll solve(int i, int used, int sum)
{
	if (i == n) return sum == used*a;
	if (dp[i][used][sum] >= 0) return dp[i][used][sum];
	ll res = 0;
	res = solve(i + 1, used + 1, sum + x[i]) + solve(i + 1, used, sum);
	return dp[i][used][sum] = res;
}

int main()
{
	cin.sync_with_stdio(false);
	MS(dp, -1);
	cin >> n >> a;
	x.resize(n);
	REP(i, n) cin >> x[i];
	cout << solve(0, 0, 0) - 1 << endl;
	return 0;
}

Submission Info

Judge Result