Submission #229162

#	Time	Username	Problem	Language	Result	Execution time	Memory
229162		wleung_bvg	Skandi (COCI20_skandi)	C++17	110 / 110	222 ms	24936 KiB

Main

#include <bits/stdc++.h>
using namespace std;
template<class C>constexpr int sz(const C&c){return int(c.size());}
using ll=long long;constexpr const char nl='\n',sp=' ';

template <const int MAXV> struct HopcroftKarpMaxMatch {
    int mate[MAXV], lvl[MAXV], q[MAXV]; vector<int> adj[MAXV], type[2]; bool color[MAXV], inCover[MAXV], vis[MAXV];
    void addEdge(int v, int w) { adj[v].push_back(w); adj[w].push_back(v); }
    bool bfs() {
        int front = 0, back = 0;
        for (int v : type[0]) {
            if (mate[v] == -1) lvl[q[back++] = v] = 0;
            else lvl[v] = -1;
        }
        while (front < back) {
            int v = q[front++];
            for (int w : adj[v]) {
                if (mate[w] == -1) return true;
                else if (lvl[mate[w]] == -1) lvl[q[back++] = mate[w]] = lvl[v] + 1;
            }
        }
        return false;
    }
    bool dfs(int v) {
        for (int w : adj[v]) if (mate[w] == -1 || (lvl[mate[w]] == lvl[v] + 1 && dfs(mate[w]))) { mate[mate[v] = w] = v; return true; }
        lvl[v] = -1; return false;
    }
    void init(int V) { for (int i = 0; i < V; i++) { adj[i].clear(); color[i] = false; } }
    int getMaxMatch(int V) {
        int cardinality = 0;
        for (int i = 0; i < 2; i++) type[i].clear();
        for (int v = 0; v < V; v++) { type[color[v]].push_back(v); mate[v] = -1; }
        while (bfs()) for (int v : type[0]) if (mate[v] == -1 && dfs(v)) cardinality++;
        return cardinality;
    }
    void dfsVertexCover(int v) {
        if (vis[v]) return;
        vis[v] = true;
        for (int w : adj[v]) if ((mate[v] == w) == color[v]) dfsVertexCover(w);
    }
    void getVertexCover(int V) {
        fill(vis, vis + V, false);
        for (int v : type[0]) if (mate[v] == -1) dfsVertexCover(v);
        for (int v = 0; v < V; v++) inCover[v] = vis[v] == color[v];
    }
};

const int MAXNM = 505;

int N, M;
string G[MAXNM];
HopcroftKarpMaxMatch<MAXNM * MAXNM * 2> mm;

int getUp(int i, int j) {
    if (G[i][j] == '1') return i * M + j;
    return getUp(i - 1, j);
}

int getLeft(int i, int j) {
    if (G[i][j] == '1') return N * M + i * M + j;
    return getLeft(i, j - 1);
}

int main() {
    // freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    // freopen("err.txt", "w", stderr);
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> N >> M;
    mm.init(N * M * 2);
    fill(mm.color, mm.color + N * M, true);
    for (int i = 0; i < N; i++) cin >> G[i];
    for (int i = 0; i < N; i++) for (int j = 0; j < M; j++) if (G[i][j] == '0') mm.addEdge(getUp(i, j), getLeft(i, j));
    cout << mm.getMaxMatch(N * M * 2) << nl;
    mm.getVertexCover(N * M * 2);
    for (int i = 0; i < N; i++) for (int j = 0; j < M; j++) if (G[i][j] == '1') {
        if (mm.inCover[i * M + j] && mm.mate[i * M + j] != -1) cout << i + 1 << sp << j + 1 << sp << "DOLJE" << nl;
        if (mm.inCover[N * M + i * M + j] && mm.mate[N * M + i * M + j] != -1) cout << i + 1 << sp << j + 1 << sp << "DESNO" << nl;
    }
    return 0;
}

• Subtask 1: 18 / 18
• Subtask 2: 32 / 32
• Subtask 3: 60 / 60