Submission #958839

#	Time	Username	Problem	Language	Result	Execution time	Memory
958839		vjudge1	Dango Maker (JOI18_dango_maker)	C++17	13 / 100	1 ms	600 KiB

dango_maker

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector <ll>;

const ll MAXN = 3E3+16;
char mat[MAXN][MAXN];

struct DSU {
    vll par, sz;
    vll blue, red;
    ll n;
    
    DSU (ll n): par(n), sz(n, 1), blue(n, 0), red(n, 0), n(n) { iota(par.begin(), par.end(), 0); }

    ll find (ll u) { return (u == par[u] ? u : par[u] = find(par[u])); }

    void join (ll u, ll v) {
        u = find(u); v = find(v);
        if (u == v) return;
        if (sz[u] > sz[v]) swap(u, v);
        par[u] = v;
        sz[v] += sz[u];
        blue[v] += blue[u];
        red[v] += red[u];
    }

    void makeRed (ll u) { red[find(u)]++; }
    void makeBlue (ll u) { blue[find(u)]++; }
};

int main () {
    cin.tie(nullptr) -> sync_with_stdio(false);
    ll n, m;
    cin >> n >> m;
    for (ll i = 0; i < n; i++) {
        for (ll j = 0; j < m; j++) {
            cin >> mat[i][j];
            if (mat[i][j] == 'R') mat[i][j] = '1';
            if (mat[i][j] == 'G') mat[i][j] = '2';
            if (mat[i][j] == 'W') mat[i][j] = '3';
        }
    }
    auto isBlue = [&](ll i, ll j) {
        // 0 <= i < n
        // 0 <= j < m-2
        if (m-2 <= j) return false;
        return mat[i][j] == '1' && mat[i][j+1] == '2' && mat[i][j+2] == '3';
    };
    auto isRed = [&](ll i, ll j) {
        // 0 <= i < n-2
        // 0 <= j < m
        if (n-2 <= i) return false;
        return mat[i][j] == '1' && mat[i+1][j] == '2' && mat[i+2][j] == '3';
    };
    ll ans = 0;
    for (ll sum = 0; sum <= n+m-2; sum++) {
        ll il = max(0LL, sum-m+1), ir = min(n, sum+1);
        DSU dsu(ir-il+16);
        for (ll i = il-5; i < ir+5; i++) {
            ll j = sum-i;
            if (0 <= i && i < n && 0 <= j && j < m) {
                if (isBlue(i, j)) {
                    dsu.makeBlue(j);
                    dsu.join(j+2, j+1);
                    dsu.join(j+1, j);
                }
                if (isRed(i, j)) {
                    dsu.makeRed(j);
                    dsu.join(j+2, j+3);
                    dsu.join(j+3, j+4);
                }
            }
        }
        for (ll i = 0; i < dsu.n; i++) {
            if (dsu.par[i] == i) ans += max(dsu.blue[i], dsu.red[i]);
        }
    }
    cout << ans << '\n';
    return 0;
}

• Subtask 1: 13 / 13
• Subtask 2: 0 / 20
• Subtask 3: 0 / 67