Submission #862631

#	Time	Username	Problem	Language	Result	Execution time	Memory
862631		Mizo_Compiler	Magneti (COCI21_magneti)	C++14	0 / 110	195 ms	4700 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double ld;
#define pb push_back
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define F first
#define S second
const int N = 50, M = 1e9+7, L = 1e4;
int n, l, r[N];
ll fact[L+2], dp[N][L+1];

ll fp(ll b, ll p) {
	ll ret = 1;
	while (p) {
		if ((p & 1))ret = (ret * b) % M;
		b = (b * b) % M;
		p >>= 1;
	}
	return ret;
}

ll nCr(int a, int b) {
	return (fact[a] * fp((fact[b] * fact[n-b])%M, M-2))%M;
}

ll sol(int i, int j) {
	if (i == n)return 1;
	if (j > l)return 0;
	ll &ret = dp[i][j];
	if (~ret)return ret;
	return ret = (sol(i, j+1) + sol(i+1, j + r[0]))%M;
}

int main () {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin >> n >> l;
	fact[0] = 1;
	for (ll i = 1; i <= L; i++) {
		fact[i] = (fact[i-1] * i) % M;
	}
	for (int i = 0; i < n; i++) {
		cin >> r[i];
	}
	if (n <= 10) {
		sort(r, r+n);
		ll ans = 0;
		do {
			ll len = 1;
			for (int i = 1; i < n; i++) {
				len += r[i-1];
			}
			if (len > l)continue;
			len %= M;
			ans += (len * fp(n, l - len)) % M;
		} while(next_permutation(r, r+n));
		cout << ans << "\n";
		return 0;
	}
	memset(dp, -1, sizeof dp);
	cout << sol(0, 1);
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 30
• Subtask 4: 0 / 50