Submission #1277398

#	Time	Username	Problem	Language	Result	Execution time	Memory
1277398		shirokito	Dango Maker (JOI18_dango_maker)	C++20	100 / 100	1277 ms	233044 KiB

dango_maker

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

using ll = long long;

const int N = 3000 + 24;

int n, m; char a[N][N]; int id[N][N];
vector<vector<int>> g;
int tdfs = 0; vector<int> mr, vis; vector<bool> ml;

bool ok(int i, int j, int dir) {
    if (dir == 0) {
        return (j + 2 <= m && a[i][j] == 'R' && a[i][j + 1] == 'G' && a[i][j + 2] == 'W');
    }
    else {
        return (i + 2 <= n && a[i][j] == 'R' && a[i + 1][j] == 'G' && a[i + 2][j] == 'W');
    }
}

bool kuhn(int u) {
    if (vis[u] == tdfs) return 0;
    vis[u] = tdfs;

    for (int v: g[u]) {
        if (mr[v] == 0 || kuhn(mr[v])) {
            mr[v] = u;
            return 1;
        }
    }

    return 0;
}

void solve() {
    cin >> n >> m;

    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
        }
    }

    int szL = 0, szT = 0;

    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (ok(i, j, 0)) ++szL;
            if (ok(i, j, 1)) id[i][j] = ++szT;
        }
    }

    g.assign(szL + 1, vector<int>());
    mr.resize(szT + 1, 0); vis.resize(szL + 1, 0);
    ml.resize(szL + 1, 0);

    szL = 0;

    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (!ok(i, j, 0)) continue;
            szL++;
            if (ok(i, j, 1)) g[szL].push_back(id[i][j]);
            if (i - 1 >= 1 && j + 1 <= m && ok(i - 1, j + 1, 1)) g[szL].push_back(id[i - 1][j + 1]);
            if (i - 2 >= 1 && j + 2 <= m && ok(i - 2, j + 2, 1)) g[szL].push_back(id[i - 2][j + 2]);
        }
    }

    int cnt_match = 0;
    for (bool run = true; run;) {
        run = false; ++tdfs;
        for (int i = 1; i <= szL; i++) {
            if (!ml[i] && kuhn(i)) {
                run = true;
                cnt_match++;
                ml[i] = true;
            }
        }
    }

    cout << (szL + szT) - cnt_match << '\n';
}   

int main() {
    cin.tie(0) -> sync_with_stdio(0);

    int T = 1; // cin >> T;
    while (T--) {
        solve();
    }
}

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