Submission #1370859

#TimeUsernameProblemLanguageResultExecution timeMemory
1370859Ekber_EkberTracks in the Snow (BOI13_tracks)C++20
17.60 / 100
895 ms1114112 KiB
#include <bits/stdc++.h>
// #ifndef ONLINE_JUDGE
//     #include <debug.h>
// #else
//     #define debug(...)
// #endif
#define GOOD_LUCK ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
// #define int long long
#define endl "\n"
#define ff first
#define ss second
#define pb push_back
#define all(v) v.begin(), v.end()
using namespace std;

int dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1};
constexpr int MAX = 4e+3 + 1, INF = 2e+9, MOD = 1e+9 + 7, K = 31;
int n, m;
vector <vector <char>> v;
vector <vector <char>> col;
vector <pair<int16_t, int16_t>> a, b;

void dfs(int ux, int uy, char c) {
    col[ux][uy] = 1;
    a.pb({ux, uy});
    for (int z = 0; z < 4; z++) {
        int ix = ux + dx[z], iy = uy + dy[z];
        if (ix < 0 || iy < 0 || ix >= n || iy >= m) continue;
        if (v[ix][iy] != c) continue;
        if (col[ix][iy]) continue;
        dfs(ix, iy, c);
    }
}

void bfs(char c) {
    b.clear();
    queue <pair<int, int>> q;
    for (auto [x, y] : a) q.push({x, y});
    while (!q.empty()) {
        auto [ux, uy] = q.front();
        q.pop();
        for (int z = 0; z < 4; z++) {
            int ix = ux + dx[z], iy = uy + dy[z];
            if (ix < 0 || iy < 0 || ix >= n || iy >= m) continue;
            if (col[ix][iy]) continue;
            if (v[ix][iy] != c) continue;
            b.pb({ix, iy});
            q.push({ix, iy});
            col[ix][iy] = 1;
        }
    }
    a.swap(b);
}

void _() {
    cin >> n >> m;
    col.assign(n, vector <char>(m, 0));
    v.assign(n, vector <char>(m, 0));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            char x;
            cin >> x;
            if (x == 'F') v[i][j] = 1;
            else v[i][j] = 2;
        }
    }
    dfs(0, 0, v[0][0]);
    char id = 3 - v[0][0];
    int res = 0;
    while (!a.empty()) {
        bfs(id);
        res++;
        id = 3 - id;
    }
    cout << res;
}

signed main() {

    GOOD_LUCK

    int tests=1;
    // cin >> tests;
    for (int i=1; i <= tests; i++) {
        _();
        cout << endl;
    }

    return 0;
}
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