Submission #1267918

#	Time	Username	Problem	Language	Result	Execution time	Memory
1267918		kawhiet	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	459 ms	111944 KiB

tracks

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

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

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, m;
    cin >> n >> m;
    vector<string> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    auto inside = [&](int x, int y) {
        return (x >= 0 && x < n && y >= 0 && y < m && a[x][y] != '.');
    };
    vector<vector<int>> dp(n, vector<int>(m));
    deque<pair<int, int>> q;
    q.push_back({0, 0});
    dp[0][0] = 1;
    int res = 0;
    while (!q.empty()) {
        auto [x, y] = q.front();
        q.pop_front();
        res = max(res, dp[x][y]);
        for (int i = 0; i < 4; i++) {
            int nx = x + dx[i];
            int ny = y + dy[i];
            if (inside(nx, ny) && dp[nx][ny] == 0) {
                if (a[x][y] == a[nx][ny]) {
                    dp[nx][ny] = dp[x][y];
                    q.push_front({nx, ny});
                } else {
                    dp[nx][ny] = dp[x][y] + 1;
                    q.push_back({nx, ny});
                }
            }
        }
    }
    cout << res << '\n';
    return 0;
}

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