Submission #839049

#	Time	Username	Problem	Language	Result	Execution time	Memory
839049		guagua0407	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	126 ms	81920 KiB

skyscraper

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

const int mxn=105;
const int mxl=1005;
const int mod=1e9+7;

ll dp[mxn][mxn][mxl][3];
int a[mxn];

int main() {_
    int n,L;
    cin>>n>>L;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    if(n==1){
        cout<<1<<'\n';
        return 0;
    }
    sort(a+1,a+n+1);
    dp[1][1][0][0]=1;
    dp[1][1][0][1]=2;
    ll ans=0;
    for(int i=1;i<n;i++){
        int diff=a[i+1]-a[i];
        for(int j=1;j<=i;j++){
            for(int k=0;k<=L;k++){
                // new
                for(int m=0;m<3;m++){
                    if(k+diff*(2*j-m)>L) continue;
                    dp[i+1][j+1][k+diff*(2*j-m)][m]=(dp[i+1][j+1][k+diff*(2*j-m)][m]+dp[i][j][k][m])%mod;
                    if(m<2) dp[i+1][j+1][k+diff*(2*j-m)][m+1]=(dp[i+1][j+1][k+diff*(2*j-m)][m+1]+dp[i][j][k][m]*(1+(m==0)))%mod;
                }
                // continue
                for(int m=0;m<3;m++){
                    if(k+diff*(2*j-m)>L) continue;
                    dp[i+1][j][k+diff*(2*j-m)][m]=(dp[i+1][j][k+diff*(2*j-m)][m]+dp[i][j][k][m]*(2*j-m))%mod;
                }
                if(k+diff*(2*j-0)<=L) dp[i+1][j][k+diff*(2*j-0)][1]=(dp[i+1][j][k+diff*(2*j-0)][1]+dp[i][j][k][0]*(2*j))%mod;
                if(k+diff*(2*j-1)<=L) dp[i+1][j][k+diff*(2*j-1)][2]=(dp[i+1][j][k+diff*(2*j-1)][2]+dp[i][j][k][1]*(j-1+(i==n-1 and j==1)))%mod;
                // combine
                for(int m=0;m<3;m++){
                    if(k+diff*(2*j-m)>L) continue;
                    dp[i+1][j-1][k+diff*(2*j-m)][m]=(dp[i+1][j-1][k+diff*(2*j-m)][m]+dp[i][j][k][m]*(j*(j-1)-(j-1)*m+(i==n-1 and m==2)))%mod;
                }
            }
        }
    }
    for(int i=0;i<=L;i++){
        ans=(ans+dp[n][1][i][2])%mod;
    }
    cout<<ans<<'\n';
    return 0;
}
//maybe its multiset not set

Compilation message (stderr)

skyscraper.cpp: In function 'void setIO(std::string)':
skyscraper.cpp:12:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:13:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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