Submission #382595

#	Time	Username	Problem	Language	Result	Execution time	Memory
382595		ritul_kr_singh	Tracks in the Snow (BOI13_tracks)	C++17	12.08 / 100	1386 ms	543648 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define sp << " " <<
#define nl << "\n"

vector<int> e;
int find(int u){
	return e[u] < 0 ? u : e[u] = find(e[u]);
}
void unite(int u, int v){
	u = find(u), v = find(v);
	if(u==v) return;
	if(e[u] > e[v]) swap(u, v);
	e[u] += e[v], e[v] = u;
}

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

signed main(){
	cin.tie(0)->sync_with_stdio(0);
	int h, w; cin >> h >> w;
	int g[h][w];
	bool vis[h][w];
	e.assign(h*w, -1);
	queue<array<int, 3>> q;
	for(int i=0; i<h; ++i){
		for(int j=0; j<w; ++j){
			char c; cin >> c;
			if(c=='.') g[i][j] = 0;
			if(c=='F') g[i][j] = 1;
			if(c=='R') g[i][j] = 2;
			if(i and g[i-1][j]==g[i][j]) unite(i*w + j, i*w + j - w);
			if(j and g[i][j-1]==g[i][j]) unite(i*w + j, i*w + j - 1);
			vis[i][j] = false;
		}
	}
	for(int i=0; i<h; ++i){
		for(int j=0; j<w; ++j){
			if(find(i*w + j)==find(0)) q.push({i, j, 1}), vis[i][j] = true;
		}
	}
	int ans = 0;
	while(!q.empty()){
		int x = q.front()[0], y = q.front()[1], d = q.front()[2]; q.pop();
		for(int k=0; k<4; ++k){
			int i = x + dx[k], j = y + dy[k];
			if(i>=0 and j>=0 and i!=h and j!=w and g[i][j]==3-g[x][y] and !vis[i][j]){
				q.push({i, j, d+1});
				vis[i][j] = true;
			}
		}
		ans = max(ans, d);
	}
	cout << ans;
}

• Subtask 1: 3.3333333333333335 / 30
• Subtask 2: 8.75 / 70