Submission #236945

#	Time	Username	Problem	Language	Result	Execution time	Memory
236945		aggu_01000101	Tents (JOI18_tents)	C++14	100 / 100	342 ms	70904 KiB

tents

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int MOD = 1000000007;
signed main(){
    ios_base::sync_with_stdio(false);
    int h, w;
    cin>>h>>w;
    int dp[h+1][w+1];
    dp[1][1] = 5;
    for(int i = 0;i<=h;i++) dp[i][0] = 1;
    for(int i = 0;i<=w;i++) dp[0][i] = 1;
    for(int i = 2;i<=h;i++){
        dp[i][1] = dp[i-1][1] + (i-1) + 4;
    }
    for(int j = 2;j<=w;j++){
        for(int i = 1;i<=h;i++){
            dp[i][j] = dp[i][j-1];
            dp[i][j]%=MOD;
            dp[i][j] += (((i*(j-1))%MOD)*dp[i-1][j-2])%MOD;
            dp[i][j]%=MOD;
            dp[i][j] += (4*i*dp[i-1][j-1])%MOD;
            dp[i][j]%=MOD;
            if(i>1) dp[i][j] += ((((i*(i-1))/2)%MOD) * (dp[i-2][j-1]))%MOD;
            dp[i][j]%=MOD;
        }
    }
    int ans = (dp[h][w] - 1 + MOD)%MOD;
    cout<<ans<<"\n";
}

• Subtask 1: 48 / 48
• Subtask 2: 52 / 52