Submission #1222175

#	Time	Username	Problem	Language	Result	Execution time	Memory
1222175		firegirlwaterboy	Tracks in the Snow (BOI13_tracks)	C++20	77.50 / 100	524 ms	112140 KiB

tracks

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

int dx[4] = {1, -1, 0, 0}, dy[4] = {0, 0, 1, -1};

void solve() {
    int n, m;
    cin >> n >> m;
    vector<string> grid(n);
    for (int i = 0; i < n; i++) {
        cin >> grid[i];
    }
    deque<pii> q;
    q.push_front({0, 0});
    vector<vector<int>> d(n, vector<int>(n));
    d[0][0] = 1;
    int ans = 1;
    while (q.size()) {
        pii c = q.front();
        q.pop_front();
        int x = c.first, y = c.second;
        ans = max(ans, d[x][y]);
        for (int i = 0; i < 4; i++) {
            int nx = x + dx[i], ny = y + dy[i];
            if (nx < 0 || nx >= n || ny < 0 || ny >= m || grid[nx][ny] == '.')
                continue;
            if (d[nx][ny]) continue;
            if (grid[nx][ny] == grid[x][y]) {
                d[nx][ny] = d[x][y];
                q.push_front({nx, ny});
            } else {
                d[nx][ny] = d[x][y] + 1;
                q.push_back({nx, ny});
            }
        }
    }
    cout << ans << "\n";
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
    return 0;
}

• Subtask 1: 25 / 30
• Subtask 2: 52.5 / 70