Submission #965554

#	Time	Username	Problem	Language	Result	Execution time	Memory
965554		OIaspirant2307	Tracks in the Snow (BOI13_tracks)	C++17	2.19 / 100	1959 ms	406092 KiB

tracks

#include <iostream>
#include <vector>
#include <queue>
using namespace std;
#define int long long
#define pi pair<int, int>
#define f first
#define s second
const int N = 4005;
vector<vector<char>> grid(N, vector<char>(N));
vector<vector<bool>> vis(N, vector<bool>(N, 0));
vector<pi> rabbits;
vector<pi> foxes;
vector<pi> moves = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
int n, m;

bool ok(int i, int j)
{
    return (i >= 0 && i < n && j >= 0 && j < m && grid[i][j] != '.' && !vis[i][j]);
}

void bfs(pi pos)
{
    queue<pi> q;
    q.push({pos.f, pos.s});
    vis[pos.f][pos.s] = true;
    while (!q.empty())
    {
        auto p = q.front();
        q.pop();
        for (auto move : moves)
        {
            if (ok(p.f + move.f, p.s + move.s))
            {
                vis[p.f + move.f][p.s + move.s] = true;
                q.push({p.f + move.f, p.s + move.s});
            }
        }
    }
}

signed main()
{
    cin >> n >> m;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            cin >> grid[i][j];
            if (grid[i][j] == 'R')
            {
                rabbits.push_back({i, j});
            }
            else if (grid[i][j] == 'F')
            {
                foxes.push_back({i, j});
            }
        }
    }
    int ans = 0;
    for (auto p : rabbits)
    {
        if (!vis[p.f][p.s])
        {
            bfs({p.f, p.s});
            ans++;
        }
    }
    for(int i = 0; i < n; i++){
        for(int j = 0; j < m; j++){
            vis[i][j] = false;
        }
    }
    for (auto p : foxes)
    {
        if (!vis[p.f][p.s])
        {
            bfs({p.f, p.s});
            ans++;
        }
    }
    cout << ans << '\n';
}

• Subtask 1: 0 / 30
• Subtask 2: 2.1875 / 70