Submission #122644

#	Time	Username	Problem	Language	Result	Execution time	Memory
122644		ZwariowanyMarcin	Skyscraper (JOI16_skyscraper)	C++14	15 / 100	2 ms	760 KiB

skyscraper

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>


#define pb push_back
#define ld long double
#define fi first
#define se second
#define ll long long
#define ss(x) (int) x.size()
#define mp make_pair
#define FOR(i, n) for(int i = 1; n >= i; ++i)

using namespace std;
using namespace __gnu_pbds;

const int nax = 105, mod = 1e9 + 7;

int n, s;
int a[nax];
int dp[nax][nax][1005][3];

void add(int &a, int b) {
	a += b;
	if(a >= mod)
		a -= mod;
}

int jazda(int x, int y) {
	int normal = x - y;
	int odp = normal * (normal - 1);
	odp += y * (x - 1);
	if(y == 2)
		odp -= 2;
	odp %= mod;
	return odp;
}

int main() {
	
	cin.tie(0);
	ios_base::sync_with_stdio(0);
	
	cin >> n >> s;
	for(int i = 1; i <= n; ++i) {
		cin >> a[i];
	}
	
	sort(a + 1, a + n + 1);
	
	dp[0][0][0][0] = 1;
	for(int i = 0; i < n; ++i) {
		for(int j = 0; j <= n; ++j) {
			for(int sum = 0; sum <= s; ++sum) {
				for(int ile = 0; ile <= 2; ++ile) {
					if(dp[i][j][sum][ile] == 0)
						continue;	
					int val = dp[i][j][sum][ile];
				//5	cout << i << " " << j << " " << sum << " " << ile << " " << val << endl;
					// 1. dodaj 1
					// cout << dp[2][0][9][1] << " 1" << endl;
					int dodatek = 2 * (j + 1) - ile;
					int nsum = sum + dodatek * (a[i + 2] - a[i + 1]);
					if(nsum <= s && i < n - 1)
					add(dp[i + 1][j + 1][nsum][ile], val);
				
					// 2. dodaj kraniec + 1 
					if(ile <= 1 && i < n - 1) {
						dodatek = 2 * (j + 1) - ile - 1;
						nsum = sum + dodatek * (a[i + 2] - a[i + 1]);
						if(nsum <= s)
						add(dp[i + 1][j + 1][nsum][ile + 1], (ll) val * (ile == 0 ? 2 : 1) % mod);
					}
					//cout << dp[2][0][9][1] << " 3" << endl;
					// 3. dodaj kraniec + 0
					if(ile <= 1 && j >= 1 && j > ile) {
						dodatek = 2 * j - ile - 1;
						nsum = sum + dodatek * (a[i + 2] - a[i + 1]);
						// cout << i << " " << nsum << "AAA" << " " << dodatek << endl;
						if(nsum <= s)
						add(dp[i + 1][j][nsum][ile + 1], (ll) (j - ile) * val * (ile == 0 ? 2 : 1) % mod);
					}
					// cout << dp[2][0][9][1] << " 4" << endl;
					// 4. end
					if(i == n - 1 && ile == 2 && j == 2) {
						dodatek = 2 * (j - 1) - ile;
						nsum = sum;
						//cout << i << " " << nsum << "BBB" << endl;
						if(nsum <= s)
							add(dp[i + 1][j - 1][nsum][ile], val);
					}
					if(i == n - 1 && ile == 1 && j == 1) {
						nsum = sum;
						// cout << nsum << "a" << endl;
						add(dp[i + 1][j][nsum][2], val);
					}
					// cout << dp[2][0][9][1] << " 5" << endl;
					// 5. + 0
					if(j >= 1 && i < n - 1) {
						dodatek = 2 * j - ile;
						nsum = sum + dodatek * (a[i + 2] - a[i + 1]);
						if(nsum <= s)
						add(dp[i + 1][j][nsum][ile], (ll) val * ((j - ile) * 2 + ile) % mod);
					}
					// cout << dp[2][0][9][1] << endl;
					// 6. polacz
					if(j >= 2 && j - ile > 0 && i < n - 1) {
						// cout << "CCC" << i << " " << j << " " << ile << endl;
						dodatek = 2 * (j - 1) - ile;
						nsum = sum + dodatek * (a[i + 2] - a[i + 1]);
						if(nsum <= s)
						add(dp[i + 1][j - 1][nsum][ile], (ll) val * (jazda(j, ile)) % mod);
					}
					// cout << dp[2][0][9][1] << endl;
				}
			}
		}
	}
	int ans = 0;
	for(int i = 0; i <= s; ++i) {
		// cout << dp[n][1][i][2] << endl;
		add(ans, dp[n][1][i][2]);
	}
	cout << ans;				
					
					
					
						
						
						
		
		

    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 80