제출 #853976

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
853976		NotLinux	Magneti (COCI21_magneti)	C++17	110 / 110	326 ms	204636 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e4 + 7;
const int mod = 1e9 + 7;
inline void add(int &x , int &y , int coef){
	x = (x + y * coef % mod) % mod;
}
inline int fastpow(int a , int b){
	if(b == 0)return 1;
	if(b == 1)return a;
	int val = fastpow(a,b/2);
	return val * val % mod * (b&1?a:1) % mod;
}
void solve(){
	int fact[N],invfact[N];
	fact[0] = invfact[0] = 1;
	for(int i = 1;i<N;i++){
		fact[i] = fact[i-1] * i % mod;
		invfact[i] = fastpow(fact[i] , mod-2);
	}

	function < int (int , int) > Cr = [&](int n , int r){//n tane sepete , x tane top
		return fact[n] * invfact[r] % mod * invfact[n-r] % mod;
	};

	int n,l;
	cin >> n >> l;
	int arr[n];
	for(int i = 0;i<n;i++){
		cin >> arr[i];
	}
	sort(arr , arr + n);
	int dp[n+1][n+1][l+5];
	memset(dp , 0 , sizeof(dp));
	dp[0][0][0] = 1;
	for(int i = 0;i<n;i++){
		for(int j = 0;j<n;j++){
			for(int k = 0;k<=l;k++){
				/*if(dp[i][j][k]){
					cout << i << " " << j << " " << k << " => " << dp[i][j][k] << endl;
				}*/
				//create a new component
				add(dp[i+1][j+1][k + 1] , dp[i][j][k] , j+1);
				//add to the right and left
				if((k + arr[i]) <= l){
					add(dp[i+1][j][k + arr[i]] , dp[i][j][k] , 2 * j % mod);
				}
				//merge two components
				if(j > 1 and (k + 2 * arr[i] - 1) <= l){
					add(dp[i+1][j-1][k + 2 * arr[i] - 1] , dp[i][j][k] , j-1);
				}
			}
		}
	}
	int ans = 0;
	for(int i = 0;i<l;i++){//i = boşluk miktarı
		int locans = dp[n][1][l - i] * Cr(n + i, n) % mod;
		add(ans , locans , 1);
	}
	cout << ans << endl;
}
signed main(){
	ios_base::sync_with_stdio(0);cin.tie(0);
	int testcase = 1;//cin >> testcase;
	while(testcase--)solve();
}

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