Submission #839797

#	Time	Username	Problem	Language	Result	Execution time	Memory
839797		Kavelmydex	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	663 ms	180704 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
typedef long long ll; 
typedef vector <ll> vi;
typedef pair <ll,ll> pi;
#define f first
#define s second

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

bool inside(int x, int y){
    return x >= 0 && y >= 0 && x < n && y < m && grid[x][y] != '.';
}

int main() {
    //ios::sync_with_stdio(0); cin.tie(0);
    //freopen("guard.in", "r", stdin);
    //freopen("guard.out", "w", stdout);

    cin >> n >> m;
    for(int i=0; i<n; i++){
        cin >> grid[i];
    }

    deque <pi> q;
    q.push_back({0, 0});
    depth[0][0] = 1;
    while(q.size()){
        int u = q.front().f, v = q.front().s;
        ans = max(ans, depth[u][v]);
        q.pop_front();
        for(int i=0; i<4; i++){
            int x = u + dx[i], y = v + dy[i];
            if(!inside(x, y) || depth[x][y] != 0) continue;

            if(grid[u][v] == grid[x][y]){
                depth[x][y] = depth[u][v];
                q.push_front({x, y});
            }else{
                depth[x][y] = depth[u][v] + 1;
                q.push_back({x, y});
            }
        }
    }
    cout << ans;
    return 0;
}   

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