Submission #1042326

#	Time	Username	Problem	Language	Result	Execution time	Memory
1042326		1L1YA	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	63 ms	5636 KiB

skyscraper

//1L1YA

#include<bits/stdc++.h>
using namespace std;

//#pragma GCC optimize ("O3,unrool-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

typedef long long       ll;
typedef pair<ll,ll>     pll;
typedef pair<int,int>   pii;

#define Pb              push_back
#define F               first
#define S               second
#define endl            '\n'
#define sep             ' '
#define all(x)          x.begin(),x.end()
#define al(x,n)         x+1,x+n+1
#define SZ(x)           ((int)x.size())
#define lc              (id<<1)
#define rc              (lc|1)
#define mid             (l+r>>1)
#define dokme(x)        cout << x << endl, exit(0)
#define sik(x)          cout << x << endl;continue;
#define FastIO          ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define FileIO          freopen("input.txt","r",stdin);freopen("output.txt","w",stdout);

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ll oo=1e18;
const int mod=1e9+7;
const int inf=1e9+111;
const int N=111;
const int M=1011;
const int lg=23;

ll n,m,a[N],dp[M][N][3],DP[M][N][3];

int main(){
	FastIO

	cin >> n >> m;
	for(int i=1;i<=n;i++)	cin >> a[i];
	if(n==1)	dokme(1);
	sort(al(a,n));
	DP[0][0][0]=1;
	a[n+1]=1e5;
	for(int i=1;i<=n;i++){
		for(int j=0;j<=m;j++)
			for(int k=1;k<=i;k++)
				for(int c=0;c<3;c++){
					int p=2*k-c,w=j-p*(a[i+1]-a[i]);
					dp[j][k][c]=0;
					if(w<0)	continue;
					dp[j][k][c]=(DP[w][k-1][c]*(k-c)+DP[w][k][c]*p+DP[w][k+1][c]*k)%mod;
					if(c)	dp[j][k][c]=(dp[j][k][c]+DP[w][k-1][c-1]*(3-c)+DP[w][k][c-1]*(3-c))%mod;
				}
		for(int j=0;j<=m;j++)
			for(int k=0;k<=i;k++)
				for(int c=0;c<3;c++)
					DP[j][k][c]=dp[j][k][c];
	}
	ll ans=0;
	for(int i=0;i<=m;i++)	ans=(ans+dp[i][1][2])%mod;
	cout << ans << endl;

	return 0;
}

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