Submission #849355

#	Time	Username	Problem	Language	Result	Execution time	Memory
849355		Artteiv	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	1311 ms	69440 KiB

tracks

#include <bits/stdc++.h>
#define ll long long
#define endl '\n'
#define pll pair<long long,long long>
#define int long long
#define pii pair<int,int>
#define FOR(i,a,b) for(int i =a; i<=b; i++)
#define ROF(i,a,b) for(int i =a; i>=b; i--)

const long long MOD = 1e9+7;

using namespace std;

vector<vector<bool>> stat;
vector<string> s;
int cur;
int w,h; 
int cn = 0;
int dx[4] = {0,1,0,-1};
int dy[4] = {1,0,-1,0};
bool ok(pii a){
	if (a.first<=h && a.first>=1 
		&& a.second<=w && a.second>=1 
		&& stat[a.first][a.second]==0) 
		return 1;
	return 0;
}
int nx(int c){
	if (c=='F') return 'R';
	return 'F';
}
void solve(){
	cin>>h>>w;
	s.resize(h+1);
	stat.resize(h+1);
	for (int i =1; i<=h; i++){
		stat[i].resize(w+1);
		cin>>s[i];
		s[i] = '#'+s[i];
	}	
	cur = s[1][1];
	bool msk = 0;
	deque<pii> bfs[2];
	bfs[msk].push_back({1,1});
	int res=0;
	while (bfs[msk].size()){
		auto [x,y] = bfs[msk].front();
		bfs[msk].pop_front();
		if (stat[x][y]){
			if (bfs[msk].empty()){
				res++;
				msk = !msk;
				cur = nx(cur);
			}
			continue;
		}
		stat[x][y]=1;
		for (int i =0; i<4; i++){
			int X = x+dx[i],Y = y+dy[i];
			if (ok({X,Y})){
				if(s[X][Y]==nx(cur)){
					bfs[!msk].push_back({X,Y});
				}
				else if (s[X][Y]==cur){
					bfs[msk].push_back({X,Y});
				}
			}
		}
		if (bfs[msk].empty()){
			res++;
			msk = !msk;
			cur = nx(cur);
		}
	}	
	cout<<res<<endl;
}

int32_t main(){
	ios_base::sync_with_stdio(0);
	cin.tie(NULL);
	cout.tie(NULL);
		solve();
	return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'void solve()':
tracks.cpp:47:8: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   47 |   auto [x,y] = bfs[msk].front();
      |        ^

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