제출 #722560

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
722560		PoPularPlusPlus	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	1858 ms	650896 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long 
#define pb(e) push_back(e)
#define sv(a) sort(a.begin(),a.end())
#define sa(a,n) sort(a,a+n)
#define mp(a,b) make_pair(a,b)
#define vf first
#define vs second
#define ar array
#define all(x) x.begin(),x.end()
const int inf = 0x3f3f3f3f;
const int mod = 1000000007; 
const double PI=3.14159265358979323846264338327950288419716939937510582097494459230;

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

bool remender(ll a , ll b){return a%b;}

//freopen("problemname.in", "r", stdin);
//freopen("problemname.out", "w", stdout);

int n , m;

int convert(int r , int w){
	return r*m+w;
}

pair<int,int> back(int x){
	return mp(x/m,x%m);
}

struct ufds {
	
	vector<int> siz,p;
	
	void init(int nn){
		siz.resize(nn + 1);
		p.resize(nn + 1);
		for(int i = 0; i <= nn; i++){
			siz[i] = 1;
			p[i] = i;
		}
	}
	
	int get(int x){
		return p[x] = (p[x] == x ? x : get(p[x]));
	}
	
	void unio(int x , int y){
		x = get(x);
		y = get(y);
		if(x == y)return;
		if(siz[y] > siz[x])swap(x,y);
		p[y] = x;
		siz[x] += siz[y];
	}
};

int dx[4] = {1,0}, dy[4] = {0,1};

void solve(){
	cin >> n;
	cin >> m;
	char arr[n][m];
	for(int i = 0; i < n; i++){
		for(int j = 0; j < m; j++)cin >> arr[i][j];
	}
	ufds dsu;
	dsu.init(n*m+1);
	for(int i = 0; i < n; i++){
		for(int j = 0; j < m; j++){
			if(arr[i][j] == '.')continue;
			for(int k = 0; k < 2; k++){
				int ni = i + dx[k] , nj = j + dy[k];
				if(ni < n && nj < m && ni >= 0 && nj >= 0 && arr[i][j] == arr[ni][nj]){
					dsu.unio(convert(i,j),convert(ni,nj));
				}
			}
		}
	}
	vector<int> adj[n*m];
	for(int i = 0; i < n; i++){
		for(int j = 0; j < m; j++){
			if(arr[i][j] == '.')continue;
			for(int k = 0; k < 2; k++){
				int ni = i + dx[k] , nj = j + dy[k];
				if(ni < n && ni >= 0 && nj < m && nj >= 0 && arr[ni][nj]!='.'){
					int a = convert(ni,nj);
					int b = convert(i,j);
					a = dsu.get(a);
					b = dsu.get(b);
					if(a==b)continue;
					adj[a].pb(b);
					adj[b].pb(a);
				}
			}
		}
	}
	int dis[n*m];
	queue<int> q;
	memset(dis,-1,sizeof dis);
	dis[dsu.get(0)] = 1;
	q.push(dsu.get(0));
	int ans = 1;
	while(q.size()){
		int node = q.front();
		q.pop();
		for(int i : adj[node]){
			int par = dsu.get(i);
			if(dis[par] == -1){
				dis[par] = dis[node] + 1;
				ans = dis[par];
				q.push(par);
			}
		}
	}
	cout << ans << '\n';
}

int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
   // int t;cin>>t;
   // while(t--){
		solve();
	//}
	return 0;
}

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