Submission #639573

#	Time	Username	Problem	Language	Result	Execution time	Memory
639573		AdiCoder03	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	1022 ms	175784 KiB

tracks

#include<bits/stdc++.h>
typedef long long ll;

#define vi vector<int>
#define pb push_back
#define self_min(a, b) a = min(a, b)
#define self_max(a, b) a = max(a, b)
#define V vector
#define yes cout<<"YES\n";
#define no cout<<"NO\n";
#define fs(lcv, hi) for(lcv = 0; lcv < hi; lcv ++)
#define fb(lcv, hi) for(lcv = hi; lcv >= 0; lcv --)
#define loop(lcv, lower, upper) for(lcv = lower; lcv < upper; lcv++)
#define crd(pii) [pii.first][pii.second]

using namespace std;

int h, w;

bool within(pair<int, int> p)
{
    int x, y;
    tie(x, y) = p;
    if(x >= 0 && x < h && y >= 0 && y < w)
    {
        return 1;
    }
    return 0;
}

pair<int, int> operator +(pair<int, int> p1, pair<int, int> p2)
{
    return {p1.first + p2.first, p1.second + p2.second};
}

void solve()
{
    int i, j;
    cin >> h;
    cin >> w;
    V<string> grid(h);
    fs(i, h) cin >> grid[i];
    vector<pair<int, int>> dx = {{-1, 0}, {1, 0}, {0, 1}, {0, -1}};
    deque <pair<int, int>> bfsq = {{0, 0}};
    V<vi> distances(h, vi(w, 0));
    V<V<bool>> vis(h, V<bool>(w, 0));
    distances[0][0] = 1;
    int ans = 0;
    while(!bfsq.empty())
    {
        pair<int, int> pt = bfsq.front();
        // cout << pt.first << " " << pt.second << " " << distances crd(pt) << "\n";
        vis crd(pt) = 1;
        self_max(ans, distances crd(pt));
        bfsq.pop_front();
        self_max(ans, distances crd(pt));
        for(auto xdx : dx)
        {
            pair<int, int> curr = pt + xdx;
            // cout << curr.first << " " << curr.second << "Hola\n";
            if(within(curr) && !vis crd(curr) && grid crd(curr) != '.')
            {
                if(grid crd(curr) != grid crd(pt))
                {
                    distances crd(curr) = distances crd(pt) + 1;
                    bfsq.push_back(curr);
                }
                else
                {
                    distances crd(curr) = distances crd(pt);
                    bfsq.push_front(curr);
                }
            }
        }
    }
    cout << ans;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    solve();
    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'void solve()':
tracks.cpp:38:12: warning: unused variable 'j' [-Wunused-variable]
   38 |     int i, j;
      |            ^

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