Submission #926716

#	Time	Username	Problem	Language	Result	Execution time	Memory
926716		htphong0909	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	556 ms	125948 KiB

tracks

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

int n, m;
int visited[4001][4001];
char arr[4001][4001];

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

bool canGo(int x, int y)
{
    return (x <= n && y <= m && min(x, y) > 0 && arr[x][y] != '.' && !visited[x][y]);
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            cin >> arr[i][j];
        }
    }
    visited[1][1] = 1;
    deque<pair<int, int>> q;
    q.emplace_front(1, 1);
    int ans = 1;
    while (!q.empty())
    {
        int ux, uy;
        tie(ux, uy) = q.front();
        q.pop_front();
        ans = max(ans, visited[ux][uy]);
        for (int i = 0; i < 4; i++)
        {
            int vx = ux + dx[i];
            int vy = uy + dy[i];
            if (!canGo(vx, vy)) continue;
            if (arr[vx][vy] == arr[ux][uy])
            {
                visited[vx][vy] = visited[ux][uy];
                q.emplace_front(vx, vy);
            }
            else
            {
                visited[vx][vy] = visited[ux][uy] + 1;
                q.emplace_back(vx, vy);
            }
        }
    }
    cout << ans;
    return 0;
}

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