Submission #526590

#	Time	Username	Problem	Language	Result	Execution time	Memory
526590		XEMPLI5	Tents (JOI18_tents)	C++17	100 / 100	83 ms	73092 KiB

tents

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

#define gc getchar_unlocked
#define fo(i, n) for (int i = 0; i < n; i++)
#define rfo(i, n) for (int i = n - 1; i >= 0; i--)
#define REP(i, a, b) for (int i = a; i < b; i++)
#define RREP(i, a, b) for (int i = a; i >= b; i--)
#define ll long long
#define si(x) scanf("%d", &x)
#define sl(x) scanf("%lld", &x)
#define ss(s) scanf("%s", s)
#define pi(x) printf("%d\n", x)
#define pl(x) printf("%lld\n", x)
#define ps(s) printf("%s\n", s)
#define deb(x) cout << #x << "=" << x << endl
#define deb2(x, y) cout << #x << "=" << x << "," << #y << "=" << y << endl
#define deb3(x, y, z) cout << #x << "=" << x << "," << #y << "=" << y << "," << #z << "=" << z << endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define clr(x) memset(x, 0, sizeof(x))
#define sortall(x) sort(all(x))
#define tr(it, a) for (auto it = a.begin(); it != a.end(); it++)
#define PI 3.1415926535897932384626

typedef pair<int, int> pii;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpii;
typedef vector<pl> vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;

int mpow(int base, int exp);
void dfs(int u, int par);

const int mod = 1'000'000'007;
const int N = 3000 + 100, M = N;

vi g[N];
ll dp[N][N], ans[N];

void solve()
{
    int h, w;
    cin >> h >> w;
    // dp[i][j] i free rows, j free coloumns
    ll ans = 0;
    fo(i, h + 1)
    {
        fo(j, w + 1)
        {
            if (i == 0 || j == 0)
                dp[i][j] = 1;
            else
            {
                // place nothing
                dp[i][j] += dp[i - 1][j];
                // place any one tent
                dp[i][j] += (4 * j * dp[i - 1][j - 1]);
                // place < >
                if (j >= 2)
                    dp[i][j] += ((((j * (j - 1)) / 2)) * dp[i - 1][j - 2]);
                // place up down
                if (i >= 2)
                    dp[i][j] += (((j * (i - 1))) * (dp[i - 2][j - 1]));
                dp[i][j] %= mod;
            }
        }
    }
    ans = dp[h][w] - 1;
    ans %= mod;
    ans += mod;
    ans %= mod;
    cout << ans << '\n';
    return;
}

int main()
{
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    srand(chrono::high_resolution_clock::now().time_since_epoch().count());

    int t = 1;
    int cs = 0;
    while (t - cs)
    {
        solve();
        cs++;
    }

    return 0;
}

int mpow(int base, int exp)
{
    base %= mod;
    int result = 1;
    while (exp > 0)
    {
        if (exp & 1)
            result = ((ll)result * base) % mod;
        base = ((ll)base * base) % mod;
        exp >>= 1;
    }
    return result;
}

void ipgraph(int n, int m)
{
    int u, v;
    while (m--)
    {
        cin >> u >> v;
        u--, v--;
        g[u].pb(v);
        g[v].pb(u);
    }
}

void dfs(int u, int par)
{
    for (int v : g[u])
    {
        if (v == par)
            continue;
        dfs(v, u);
    }
}

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