Submission #766909

#	Time	Username	Problem	Language	Result	Execution time	Memory
766909		tamyte	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	534 ms	76184 KiB

tracks

#include<bits/stdc++.h>
using namespace std;
void setIO(string name = "")
{
    cin.tie(0)->sync_with_stdio(0); // see /general/fast-io
    if (name.size())
    {
        freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
        freopen((name + ".out").c_str(), "w", stdout);
    }
}
int n, m;

bool ok(int i, int j) {
    return min(i, j) >= 0 && i < n && j < m;
}

void solve() {
    cin >> n >> m;
    vector<vector<char>> arr(n, vector<char>(m));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            cin >> arr[i][j];
        }
    }
    vector<vector<bool>> vis(n, vector<bool>(m));
    int cnt = 1;
    deque<pair<int, int>> dq;
    dq.push_front({0, 0});
    vector<int> dx = {0, 1, 0, -1}, dy = {1, 0, -1, 0};
    char now = arr[0][0];
    while (dq.size()) {
        auto c = dq.front(); dq.pop_front();
        if (arr[c.first][c.second] != now) {
            now = arr[c.first][c.second];
            cnt++;
        }
        for (int i = 0; i < 4; ++i) {
            int ii = dy[i] + c.first;
            int jj = dx[i] + c.second;
            if (!ok(ii, jj) || vis[ii][jj] || arr[ii][jj] == '.') continue;
            vis[ii][jj] = true;
            if (arr[ii][jj] != now) {
                dq.push_back({ii, jj});
            } else {
                dq.push_front({ii, jj});
            }
        }
    }
    cout << cnt << "\n";
}


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

Compilation message (stderr)

tracks.cpp: In function 'void setIO(std::string)':
tracks.cpp:8:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |         freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:9:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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