Submission #1158997

#	Time	Username	Problem	Language	Result	Execution time	Memory
1158997		75_yabuki	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	380 ms	127880 KiB

tracks

#define _DEB213UG
// #include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
// using namespace atcoder;
#define endl "\n"
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define CNT_LOWER(v, n) (ll)(lower_bound((v).begin(), (v).end(), (n)) - (v).begin())
#define CNT_UPPER(v, n) (ll)(upper_bound((v).begin(), (v).end(), (n)) - (v).begin())
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pld;
typedef vector<int> vi;
typedef vector<pii> vii;
const long double pi = acos(-1.0);
const int INF = 1987654321;
const ll LLINF = 1e18;
const double eps = 1e-9;
template<class T>bool chmax(T& a, const T& b) { if (a <= b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T& a, const T& b) { if (b <= a) { a = b; return 1; } return 0; }

//////////////////////

// #ifndef ONLINE_JUDGE
// #include "template.cpp"
// #else
// #define debug(...)
// #define debugArr(...)
// #endif

//////////////////////

const int dy[]={-1,1,0,0};
const int dx[]={0,0,-1,1};
int dist[4040][4040];
string board[4040];

int main(){
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int N,M;cin>>N>>M;
    for(int i=0;i<N;i++)cin>>board[i];
    memset(dist,-1,sizeof(dist));
    dist[0][0]=1;
    deque<pii> dq;
    dq.push_back({0,0});
    int ans=0;
    while(!dq.empty()){
        auto cur=dq.front();dq.pop_front();
        for(int dir=0;dir<4;dir++){
            int ny=cur.first+dy[dir];
            int nx=cur.second+dx[dir];
            if(ny<0||ny>=N||nx<0||nx>=M)continue;
            if(dist[ny][nx]!=-1)continue;
            if(board[ny][nx]=='.')continue;
            if(board[ny][nx]==board[cur.first][cur.second]){
                dist[ny][nx]=dist[cur.first][cur.second];
                dq.push_front({ny,nx});
            }
            else{
                dist[ny][nx]=dist[cur.first][cur.second]+1;
                dq.push_back({ny,nx});
            }
            chmax(ans,dist[ny][nx]);
        }
    }
    cout<<ans<<endl;

    return 0;
}

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