Submission #652397

#	Time	Username	Problem	Language	Result	Execution time	Memory
652397		tmarcinkevicius	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	697 ms	142940 KiB

tracks

#include<bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
#define f first
#define s second
const int MAX_W = 4005;
int N, M;
char L[MAX_W][MAX_W];
int dep[MAX_W][MAX_W];
bool vis[MAX_W][MAX_W];
pii Move[4] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};

int main ()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> N >> M;
    for (int i = 0; i <= N + 1; i++)
    {
        for (int j = 0; j < M + 1; j++)
        {
            if (i == 0 || j == 0 || i == N + 1 || j == M + 1)
            {
                L[i][j] = '.';
                continue;
            }
            cin >> L[i][j];
        }
    }
    /*for (int i = 0; i <= N + 1; i++)
    {
        for (int j = 0; j < M + 1; j++)
        {
            cout << L[i][j];
        }
        cout << '\n';
    }*/
    //cout << '\n';
    deque<pii> q;
    q.push_front({1, 1});
    int ans = 1;
    dep[1][1] = 1;
    vis[1][1] = true;
    while (!q.empty())
    {
        //cout << "size = " << q.size() << '\n';
        pii pos = q.front();
        //cout << "pos = {" << pos.f << ", " << pos.s << "}\n";
        //cout << "val: " << L[pos.f][pos.s] << '\n';
        q.pop_front();
        pii newpos;
        for (int i = 0; i < 4; i++)
        {
            newpos = {pos.f + Move[i].f, pos.s + Move[i].s};
            if (vis[newpos.f][newpos.s] || (L[newpos.f][newpos.s] != 'F' && L[newpos.f][newpos.s] != 'R')) continue;
            vis[newpos.f][newpos.s] = true;
            if (L[newpos.f][newpos.s] == L[pos.f][pos.s])
            {
                dep[newpos.f][newpos.s] = dep[pos.f][pos.s];
                q.push_front(newpos);
            }
            else
            {
                dep[newpos.f][newpos.s] = dep[pos.f][pos.s] + 1;
                ans = max(ans, dep[pos.f][pos.s] + 1);
                q.push_back(newpos);
            }
        }
    }
    cout << ans;
}

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