Submission #1116438

#	Time	Username	Problem	Language	Result	Execution time	Memory
1116438		YugiHacker	Tents (JOI18_tents)	C++17	100 / 100	103 ms	102356 KiB

tents

/*
	www.youtube.com/YugiHackerChannel
	linktr.ee/YugiHacker
*/
#include<bits/stdc++.h>
#define el cout<<"\n"
#define f0(i,n) for(int i=0;i<n;++i)
#define f1(i,n) for(int i=1;i<=n;++i)
#define maxn 5003
#define MOD 1000000007
using namespace std;

long long f[5003][5003];
int n, m;
main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//    freopen("flagger.inp", "r", stdin);
//    freopen("flagger.out", "w", stdout);
    cin >> n >> m;
    f0 (i, max(n, m) + 1) f[0][i] = f[i][0] = 1;
    f1 (i, n) f1 (j, m)
    {
        f[i][j] = f[i-1][j];
        (f[i][j] += 4 * f[i-1][j-1] * j) %= MOD;
        if (i >= 2) (f[i][j] += f[i-2][j-1] * (i-1) * j) %= MOD;
        if (j >= 2) (f[i][j] += f[i-1][j-2] * j * (j-1) / 2) %= MOD;
    }
    cout << (f[n][m] - 1 + MOD) % MOD;
}

Compilation message (stderr)

tents.cpp:15:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   15 | main()
      | ^~~~

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