Submission #380986

#	Time	Username	Problem	Language	Result	Execution time	Memory
380986		pure_mem	Skyscraper (JOI16_skyscraper)	C++14	100 / 100	123 ms	50924 KiB

skyscraper

#include <bits/stdc++.h>

#define X first
#define Y second
#define MP make_pair
#define ll long long

using namespace std;

const int N = 103;
const int mod = 1e9 + 7;

int n, d, a[N];
ll dp[N][N][1001][3];

int main () {
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	cin >> n >> d;
	for(int i = 1;i <= n;i++)
		cin >> a[i];
	sort(a + 1, a + n + 1);
	if(n == 1)
		return cout << 1, 0;
	a[n + 1] = 10000;
	dp[0][0][0][0] = 1;
	for(int i = 1;i <= n;i++){
		for(int j = 1;j <= i;j++){
			for(int k = 0;k <= d;k++){
				for(int m = 0;m < 3;m++){
					int cost = (2 * j - m) * (a[i + 1] - a[i]);
					if(cost > k || i + j + 1 - m > n)
						continue;
					dp[i][j][k][m] += dp[i - 1][j - 1][k - cost][m];
					if(m)
						dp[i][j][k][m] += (3 - m) * dp[i - 1][j - 1][k - cost][m - 1];
					dp[i][j][k][m] += (2 * j - m) * dp[i - 1][j][k - cost][m];
					if(m == 1)
						dp[i][j][k][m] += 2 * j * dp[i - 1][j][k - cost][m - 1];
					if(m == 2){
						if(i == n) 
							dp[i][j][k][m] += dp[i - 1][j][k - cost][m - 1];
						else if(j > 1)
							dp[i][j][k][m] += (j - 1) * dp[i - 1][j][k - cost][m - 1];
					}
					if(m == 2){
						if(i == n)
							dp[i][j][k][m] += dp[i - 1][j + 1][k - cost][m];
						else
							dp[i][j][k][m] += j * (j - 1) * dp[i - 1][j + 1][k - cost][m];
					}
					else if(m == 1)
						dp[i][j][k][m] += j * j * dp[i - 1][j + 1][k - cost][m];
					else
						dp[i][j][k][m] += j * (j + 1) * dp[i - 1][j + 1][k - cost][m];
					dp[i][j][k][m] %= mod;
				}
			}
		}
	}
	ll ans = 0;
	for(int i = 0;i <= d;i++)
		ans += dp[n][1][i][2];
	cout << ans % mod;
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 80 / 80