Submission #958842

#	Time	Username	Problem	Language	Result	Execution time	Memory
958842		vjudge1	Dango Maker (JOI18_dango_maker)	C++17	13 / 100	1 ms	604 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];
vector <pair <int, int> > th[2*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';
            th[i+j].push_back({ i, j });
        }
    }
    auto isBlue = [&](ll i, ll j) {
        if (0 <= i && i < n)
        if (0 <= j && j+2 < m)
            return mat[i][j] == '1' && mat[i][j+1] == '2' && mat[i][j+2] == '3';
        return false;
    };
    auto isRed = [&](ll i, ll j) {
        if (0 <= i && i+2 < n)
        if (0 <= j && j < m)
            return mat[i][j] == '1' && mat[i+1][j] == '2' && mat[i+2][j] == '3';
        return false;
    };
    ll ans = 0;
    for (ll sum = 0; sum <= n+m; sum++) {
        if (!th[sum].size()) continue;
        DSU dsu(th[sum].size()+15);
        int off = 1E9;
        for (auto [i, j] : th[sum]) off = min(off, j);
        for (auto [i, j] : th[sum]) {
            if (isBlue(i, j)) {
                dsu.makeBlue(j-off);
                dsu.join(j-off+2, j-off+1);
                dsu.join(j-off+1, j-off);
            }
            if (isRed(i, j)) {
                dsu.makeRed(j-off);
                dsu.join(j-off+2, j-off+3);
                dsu.join(j-off+3, j-off+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