Submission #1279809

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279809		kshan	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	584 ms	119872 KiB

tracks

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

int dx[4]{1, -1, 0, 0}, dy[4]{0, 0, 1, -1}, ans = 1;
int n, m;
int depth[4000][4000];
string snow[4000];

bool inside(int x, int y) {
  return (x > -1 && x < n && y > -1 && y < m && snow[x][y] != '.');
}

int main() {
  cin >> n >> m;

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

  deque<pair<int, int>> q;
  q.push_back(make_pair(0, 0));
  depth[0][0] = 1;

  while (q.size()) {
    pair<int, int> curr = q.front();
    q.pop_front();
    ans = max(ans, depth[curr.first][curr.second]);
    for (int i = 0; i < 4; i++) {
      int x = curr.first + dx[i], y = curr.second + dy[i];
      if (inside(x, y) && depth[x][y] == 0) {
        if (snow[x][y] == snow[curr.first][curr.second]) {
          depth[x][y] = depth[curr.first][curr.second];
          q.push_front(make_pair(x, y));
        } else {
          depth[x][y] = depth[curr.first][curr.second] + 1;
          q.push_back(make_pair(x, y));
        }
      }
    }
  }
  cout << ans << "\n";
}

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