Submission #1046800

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046800		idiotcomputer	Skyscraper (JOI16_skyscraper)	C++11	100 / 100	176 ms	238788 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
#define ll long long int 
 
const ll mod = 1e9+7;
 
 
 
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
 
	int n,l;
	cin >> n >> l;
 
	vector<int> h(n);
	for (int i = 0; i < n; i++) cin >> h[i];
	sort(h.begin(),h.end());
	ll dp[n][n+1][1005][3];
	memset(dp,0,sizeof(dp));
	dp[0][1][0][2] = 1;
	dp[0][1][0][1] = 2;
	int v;
	for (int i = 0; i < n-1; i++){
		for (int j = 1; j < n; j++){
			for (int k = 0; k <= l; k++){
				for (int t = 0; t < 3; t++){
					dp[i][j][k][t] = (dp[i][j][k][t])%mod;
					v = (h[i+1]-h[i]) * (2*j-(2-t));
					//if (k+v > l && dp[i][j][k][t] > 0) cout << i << " " << j << " " << k << ' ' << t << " " << v  << '\n';
					if (k + v > l) continue;
					
				//	cout << t << " " << v << ' ' << j << ' ' << i << ' ' << k << '\n';
					//appending
					dp[i+1][j][k+v][t] += dp[i][j][k][t] * (2*j-(2-t));
					if (t > 0) dp[i+1][j][k+v][t-1] += dp[i][j][k][t] * (t) * (j+t-2);
					if (t == 1 && i == n-2) dp[i+1][j][k+v][t-1] += dp[i][j][k][t];

					//combining
					dp[i+1][j-1][k+v][t] += dp[i][j][k][t] * (j-1) * (j-2+t);
					if (i == n-2 && t == 0) dp[i+1][j-1][k+v][t] += dp[i][j][k][t];

					//new cc
					dp[i+1][j+1][k+v][t] += dp[i][j][k][t];
					if (t != 0) dp[i+1][j+1][k+v][t-1] += dp[i][j][k][t] * (t);
				}
 			}
		}
	}
	if (n == 1) dp[0][1][0][0] = 1;
	ll res = 0;
	for (int i = 0; i <= l; i++) res = (res + dp[n-1][1][i][0]) % mod;
	//for (int i = 0; i <= l; i++) cout << dp[n-1][1][i][0] << " ";
//	cout << dp[n-2][1][7][1] << "\n";
//	cout << '\n';
	cout << res << '\n';
	return 0;
}
 

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