Submission #1043799

#	Time	Username	Problem	Language	Result	Execution time	Memory
1043799		lozergam	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	49 ms	51024 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define pb push_back
#define For(i, n) for(int (i) = 0 ; (i) < (n); (i)++)
#define debug(x) cout << #x << " : " << x << endl << flush
#define endl '\n'
#define sz(x) (ll)x.size()

const ll MOD = 1e9 + 7;
const ll maxn = 103;
const ll maxl = 1005;
ll dp[maxn][maxn][maxl][3];
ll a[maxn];
ll n, l;

int main()
{
	ios_base::sync_with_stdio(0);cin.tie(0);
	
	cin >> n >> l;
	
	for(int i = 1; i <= n; i++)
		cin >> a[i];
	
	if(n == 1)
	{
		cout << 1 << endl;
		exit(0);
	}
	
	sort(a + 1, a + n + 1);
	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 <= l; k++)
				for(int m = 0; m <= 2; m++)
				{
					ll delta = (2 * j - m) * (a[i + 1] - a[i]);
					
					if(delta > k)continue;
					if(i + j + 1 - m > n)continue;
					//new element make a new comp and dont have end point
					dp[i][j][k][m] += dp[i - 1][j - 1][k - delta][m];
					
					//new element make a new comp and have end point
					if(m == 1)
						dp[i][j][k][m] += 2 * dp[i - 1][j - 1][k - delta][0];
						
					else if(m == 2)
						dp[i][j][k][m] += dp[i - 1][j - 1][k - delta][1];
						
					//new element go to one of the comps but not the endpoint
					dp[i][j][k][m] += (2 * j - m) * dp[i - 1][j][k - delta][m];
					
					//new element go to one of the comps and endpoint
					if(m == 1)
						dp[i][j][k][m] += (2 * j) * dp[i - 1][j][k - delta][0];
					
					else if(m == 2 and i == n)
						dp[i][j][k][m] += dp[i - 1][j][k - delta][1];
					
					else if(m == 2)
						dp[i][j][k][m] += (j - 1) * dp[i - 1][j][k - delta][1];
						
					//new element combone two comps
					if(m == 0)
						dp[i][j][k][m] += (j * (j + 1)) * dp[i - 1][j + 1][k - delta][0];
					else if(m == 1)
						dp[i][j][k][m] += (j * (j - 1) + j) * dp[i - 1][j + 1][k - delta][1];
					else if(i == n)
						dp[i][j][k][m] += dp[i - 1][j + 1][k - delta][2];
					else
						dp[i][j][k][m] += ((2 * (j - 1)) + ((j - 1) * (j - 2))) * dp[i - 1][j + 1][k - delta][2];
						
					dp[i][j][k][m] %= MOD;
				}
				
	ll ans = 0;	
	For(i, l+1)ans += dp[n][1][i][2];
	
	cout << ans % MOD << endl;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:7:27: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
    7 | #define For(i, n) for(int (i) = 0 ; (i) < (n); (i)++)
      |                           ^
skyscraper.cpp:85:2: note: in expansion of macro 'For'
   85 |  For(i, l+1)ans += dp[n][1][i][2];
      |  ^~~

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