Submission #1283662

#	Time	Username	Problem	Language	Result	Execution time	Memory
1283662		iamhereforfun	Tents (JOI18_tents)	C++20	100 / 100	160 ms	196660 KiB

tents

// Starcraft 2 enjoyer + luv kd //

#include <bits/stdc++.h>

using namespace std;

#define LSOne(X) ((X) & -(X))

const int N = 5e3 + 5;
const int Q = 1e6 + 5;
const int M = 1e6 + 5;
const int K = 21;
const int LG = 20;
const int B = 320;
const int P = 37;
const int INF = 1e9 + 5;
const int MOD = 1e9 + 7;
const int nx[] = {0, 1, 0, -1}, ny[] = {1, 0, -1, 0};

int n, m;
long long dp[N][N];

void solve()
{
    cin >> n >> m;
    memset(dp, 0, sizeof(dp));
    dp[0][0] = 1;
    for (int x = 0; x <= n; x++)
    {
        for (int y = 0; y <= m; y++)
        {
            int rx = (n - x), ry = (m - y);
            dp[x + 2][y + 1] += dp[x][y] * ((rx - 1) * ry) % MOD;
            dp[x + 1][y + 2] += dp[x][y] * ((ry * (ry - 1)) / 2) % MOD;
            dp[x + 1][y + 1] += 4 * dp[x][y] * ry;
            dp[x + 1][y] += dp[x][y];
            dp[x + 2][y + 1] %= MOD;
            dp[x + 1][y + 2] %= MOD;
            dp[x + 1][y + 1] %= MOD;
            dp[x + 1][y] %= MOD;
            // cout << dp[x][y] << " " << x << " " << y << "\n";
        }
    }
    long long ans = 0;
    for (int x = 1; x <= m; x++)
    {
        ans += dp[n][x];
        ans %= MOD;
    }
    cout << ans;
}

signed main()
{
    // freopen("art2.in", "r", stdin);
    // freopen("art2.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    // cin >> t;
    for (int x = 1; x <= t; x++)
    {
        solve();
    }
    return 0;
}

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