Submission #715539

#	Time	Username	Problem	Language	Result	Execution time	Memory
715539		jackpost	Tracks in the Snow (BOI13_tracks)	C++14	23.13 / 100	2093 ms	226624 KiB

tracks

// IN THE NAME OF GOD
#include<bits/stdc++.h>
#define endl '\n'
#define file_reading freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
#define flush cout.flush();
using namespace std;
typedef long long ll;
typedef long double dll;
typedef unsigned long long ull;

const int N = 4e3+5; 
int dat[N][N], mark[N][N], ans, having, must; 
queue<pair<int,int>> q; 
pair<int,int> gone[N*N];  

void bfs(int n, int m){
	q.push({n,m}); 
	int x,y; 
	int ind; 
	while(having != must){
		ans++; 
		ind = 0; 
		while(q.size()){
			x = q.front().first;
			y = q.front().second; 
			q.pop(); 
			if (mark[x][y]) continue;
			gone[++ind] = {x,y}; 
			mark[x][y] = 1; 
			having++; 
			if (x > 1 && dat[x][y] == dat[x-1][y] && !mark[x-1][y]) q.push({x-1,y});
			if (x < n && dat[x][y] == dat[x+1][y] && !mark[x+1][y]) q.push({x+1,y});
			if (y > 1 && dat[x][y] == dat[x][y-1] && !mark[x][y-1]) q.push({x,y-1});
			if (y < m && dat[x][y] == dat[x][y+1] && !mark[x][y+1]) q.push({x,y+1});
		}
		for(int i=0; i<ind; i++){
			x = gone[i].first;
			y = gone[i].second;
			if (x > 1 && dat[x][y] != dat[x-1][y] && !mark[x-1][y] && dat[x][y] + dat[x-1][y] == 3) q.push({x-1,y});
			if (x < n && dat[x][y] != dat[x+1][y] && !mark[x+1][y] && dat[x][y] + dat[x+1][y] == 3) q.push({x+1,y});
			if (y > 1 && dat[x][y] != dat[x][y-1] && !mark[x][y-1] && dat[x][y] + dat[x][y-1] == 3) q.push({x,y-1});
			if (y < m && dat[x][y] != dat[x][y+1] && !mark[x][y+1] && dat[x][y] + dat[x][y+1] == 3) q.push({x,y+1});
		}
	}
}

void solve(){  
	int n,m; cin >> n >> m; 
	for(int i=1; i<=n; i++){
		for(int j=1; j<=m; j++){
			char g; cin >> g; 
			if (g == '.') dat[i][j] = 0; 
			else if (g == 'R') dat[i][j] = 1, must++; 
			else dat[i][j] = 2, must++; 
		}
	}
	bfs(n,m); 
	cout << ans << endl; 
}

int32_t main(){
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int t; t=1; //cin >> t;
	while(t--){solve();}
}

• Subtask 1: 10 / 30
• Subtask 2: 13.125 / 70