Submission #219408

#	Time	Username	Problem	Language	Result	Execution time	Memory
219408		VEGAnn	Skandi (COCI20_skandi)	C++14	55 / 110	7527 ms	8548 KiB

Main

#include <bits/stdc++.h>
#define all(x) x.begin(),x.end()
#define sz(x) ((int)x.size())
#define PB push_back
#define pii pair<int,int>
#define MP make_pair
#define ft first
#define sd second
using namespace std;
const int N = 510;
const int K = 1520;
const int oo = 2e9;
const int md = int(1e9) + 7;
vector<pii> vc[2];
vector<vector<int> > g;
vector<bool> used, was;
vector<int> mt, nm;
char c[N][N];
int n, m, mrk[N][N][2], lf[N][N];

bool try_kuhn(int v){
    if (used[v]) return 0;

    used[v] = 1;

    for (int u : g[v]){
        if (mt[u] == -1 || try_kuhn(mt[u])){
            mt[u] = v;
            return 1;
        }
    }

    return 0;
}

mt19937 rnd(chrono::system_clock().now().time_since_epoch().count());

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);

//    freopen("in.txt","r",stdin);

    cin >> n >> m;

    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++)
            cin >> c[i][j];

    for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++){
        if (j == 0){
            lf[i][j] = -1;
            if (c[i][j] == '1')
                lf[i][j] = j;
        } else {
            if (c[i][j] == '1')
                lf[i][j] = j;
            else lf[i][j] = lf[i][j - 1];
        }

        if (c[i][j] == '0') continue;

        if (i < n - 1 && c[i + 1][j] == '0') {
            mrk[i][j][0] = sz(vc[0]);
            vc[0].PB(MP(i, j));
        }

        if (j < m - 1 && c[i][j + 1] == '0') {
            mrk[i][j][1] = sz(vc[1]);
            vc[1].PB(MP(i, j));
        }
    }

    g.clear();

    for (int it = 0; it < sz(vc[0]); it++){
        g.resize(sz(g) + 1);
        g.back().clear();

        int x = vc[0][it].ft;
        int y = vc[0][it].sd;
        int xx = x + 1;

        while (xx < n && c[xx][y] == '0'){
            int yy = lf[xx][y];

            g.back().PB(mrk[xx][yy][1]);

            xx++;
        }
    }

    used.resize(sz(vc[0]));
    nm.resize(sz(vc[0]));
    was.resize(sz(vc[0]));
    mt.resize(sz(vc[1]));
    fill(all(mt), -1);
    fill(all(was), 0);

    for (int i = 0; i < sz(vc[0]); i++)
        nm[i] = i;

    shuffle(all(nm), rnd);

    for (int it = 0; it < sz(vc[0]); it++) {
        int i = nm[it];

        fill(all(used), 0);
        was[i] = try_kuhn(i);
    }

    int ans = 0;

    for (int i = 0; i < sz(vc[0]); i++)
        ans += was[i];

    cout << ans;

    return 0;
}

• Subtask 1: 9 / 18
• Subtask 2: 16 / 32
• Subtask 3: 30 / 60