Submission #1089436

#	Time	Username	Problem	Language	Result	Execution time	Memory
1089436		Alihan_8	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	599 ms	199492 KiB

tracks

#include <bits/stdc++.h>

using namespace std;

#define pb push_back

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

signed main(){
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int h, w; cin >> h >> w;
	
	vector <string> s(h);
	
	for ( auto &u: s ){
		cin >> u;
		
		for ( auto &v: u ){
			v = (v == 'F' ? 0 : v == 'R' ? 1 : 2);
		}
	}
	
	vector <vector<bool>> us(h, vector <bool> (w));
	
	auto ok = [&](int u, int v){
		return u >= 0 && u < h && v >= 0 && v < w && !us[u][v];
	};
	
	int cnt = 0, t = s[0][0];
	
	vector <pair<int,int>> q;
	
	q.pb({0, 0}); us[0][0] = 1;
	
	while ( !q.empty() ){
		vector <pair<int,int>> nxt;
		
		for ( int i = 0; i < (int)q.size(); i++ ){
			auto [u, v] = q[i];
			
			for ( int j = 0; j < 4; j++ ){
				int x = u + dx[j], y = v + dy[j];
				
				if ( !ok(x, y) ) continue;
				
				us[x][y] = 1;
				
				if ( s[x][y] == t ){
					q.pb({x, y});
				} else if ( s[x][y] != 2 ) nxt.pb({x, y});
			}
		}
		
		cnt += 1; t ^= 1;
		
		swap(nxt, q);
	}
	
	cout << cnt;
	
	cout << '\n';
}

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