Submission #792813

#	Time	Username	Problem	Language	Result	Execution time	Memory
792813		Blagoj	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	619 ms	135936 KiB

tracks

#include <bits/stdc++.h>

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

using namespace std;

#define endl '\n'
#define ll long long
#define all(x) x.begin(), x.end()

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

int n, m;

inline bool valid(int x, int y) {
    return (x >= 0 && x < n && y >= 0 && y < m);
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> m;
    vector<string> v(n);
    for (int i = 0; i < n; i++) cin >> v[i];
    deque<pair<int, int>> q;
    q.push_front({0, 0});
    bool visited[n + 2][m + 2];
    int dist[n + 2][m + 2];
    memset(visited, 0, sizeof(visited));
    memset(dist, 0, sizeof(dist));
    visited[0][0] = 1;
    dist[0][0] = 1;
    int ans = 1;
    while (q.size() > 0) {
        auto [x, y] = q.front();
        q.pop_front();
        ans = max(ans, dist[x][y]);
        for (int d = 0; d < 4; d++) {
            int nx = x + dx[d], ny = y + dy[d];
            if (valid(nx, ny) && !visited[nx][ny] && v[nx][ny] != '.') {
                visited[nx][ny] = 1;
                dist[nx][ny] = dist[x][y] + (v[nx][ny] != v[x][y]);
                if (v[nx][ny] != v[x][y]) q.push_back({nx, ny});
                else q.push_front({nx, ny});
            }
        }
    }
    cout << ans;
}

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