Submission #734451

#	Time	Username	Problem	Language	Result	Execution time	Memory
734451		rahidilbayramli	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	868 ms	130536 KiB

tracks

#include<bits/stdc++.h>
#define ll long long
#define vl vector<ll>
#define sl set<ll>
#define all(v) v.begin(), v.end()
#define pb push_back
#define s second
#define f first
#define pll pair<ll, ll>
#define pii pair<int, int>
using namespace std;
int n, m, i, j, depth[4001][4001];
int neighborx[4] = {-1, 1, 0, 0};
int neighbory[4] = {0, 0, 1, -1};
string a[4001];
bool isvalid(int c, int d)
{
    if(c < 0 || d < 0 || c >= n || d >= m || a[c][d] == '.')    return false;
    return true;
}
int main()
{
    cin >> n >> m;
    for(i = 0; i < n; i++)    cin >> a[i];
    depth[0][0] = 1;
    deque<pair<int, int>>q;
    q.push_back({0, 0});
    int ans = 0;
    while(!q.empty())
    {
        auto s = q.front();
        q.pop_front();
        int x = s.f, y = s.s;
        ans = max(ans, depth[x][y]);
        for(i = 0; i < 4; i++)
        {
            int nx = x + neighborx[i], ny = y + neighbory[i];
            if(isvalid(nx, ny) && depth[nx][ny] == 0)
            {
                if(a[x][y] == a[nx][ny])
                {
                    depth[nx][ny] = depth[x][y];
                    q.push_front({nx, ny});
                }
                else
                {
                    depth[nx][ny] = 1 + depth[x][y];
                    q.push_back({nx, ny});
                }
            }
        }
    }
    cout << ans << "\n";
}

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