Submission #475562

#	Time	Username	Problem	Language	Result	Execution time	Memory
475562		SirCovidThe19th	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	466 ms	402980 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std; 
 
#define FOR(i, x, y) for (int i = x; i < y; i++)
 
int N, L, A[105], md = 1e9 + 7; long long dp[105][105][1005][5], ans;
 
int main(){
	cin >> N >> L;
	FOR(i, 1, N + 1) cin >> A[i];
	sort(A + 1, A + N + 1); dp[0][0][0][0] = 1;
	FOR(i, 0, N + 1) FOR(j, 0, N + 1) FOR(l, 0, L + 1) FOR(m, 0, 3){
		int dif = (A[i + 1] - A[i]) * (2 * j - m); 
		long long &DP = dp[i][j][l][m]; DP %= md;
		if (dif < 0 or l + dif > L) continue;

		if (j) dp[i + 1][j - 1][l + dif][m] += DP * (j - 1); //merge
		dp[i + 1][j + 1][l + dif][m] += DP * (j + 1 - m); //new
		dp[i + 1][j][l + dif][m] += DP * (2 * j - m); //append
 
		dp[i + 1][j][l + dif][m + 1] += DP * (2 - m); //append end
		dp[i + 1][j + 1][l + dif][m + 1] += DP * (2 - m); //create end
 
		if (i == N and j == 1 and m == 2) ans += DP, ans %= md;
	}	
	cout<<(N == 1 ? 1 : ans)<<endl;
}

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