Submission #1160473

#	Time	Username	Problem	Language	Result	Execution time	Memory
1160473		spikey_86	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	382 ms	112172 KiB

tracks

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

using i64 = long long int;

void solve() {
    int n, m;
    cin >> n >> m;

    vector<string> snow(n);
    for(int i = 0; i < n; i++) cin >> snow[i];

    vector<vector<int>> depth(n + 1, vector<int>(m + 1, 0));
    depth[0][0] = 1;

    vector<int> dx = {1, -1, 0, 0}, dy = {0, 0, 1, -1};

    deque<pair<int, int>> q;
    q.push_back({0, 0});

    auto inside = [&](int x, int y) -> bool {
        return (x >= 0 && x < n && y >= 0 && y < m && snow[x][y] != '.');
    };

    int ans = 1;
    while(!q.empty()) {
        pair<int, int> u = q.front();
        q.pop_front();

        ans = max(ans, depth[u.first][u.second]);
        for(int i = 0; i < 4; i++) {
            int x = u.first + dx[i];
            int y = u.second + dy[i];

            if(inside(x, y) && !depth[x][y]) {
                if(snow[u.first][u.second] == snow[x][y]) {
                    depth[x][y] = depth[u.first][u.second];
                    q.push_front({x, y});
                } else {
                    depth[x][y] = depth[u.first][u.second] + 1;
                    q.push_back({x, y});
                }
            }
        }
    }
    cout << ans << "\n";
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;
    while(t--) {
        solve();
    }

    return 0;
}

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