Submission #924508

#	Time	Username	Problem	Language	Result	Execution time	Memory
924508		vjudge1	Maze (JOI23_ho_t3)	C++17	0 / 100	2080 ms	1052268 KiB

Main

#include <bits/stdc++.h>
 
using namespace std;
 
int R, C, N;
 
bool isBest(int d1, int d2, pair<int, int>& p){
	int mn1 = min(d1, d2);
	int mx1 = max(d1, d2);
	int mn2 = min(p.first, p.second);
	int mx2 = max(p.first, p.second);
	if(!((mx1 <= N && mn1 < N) || (mx2 <= N && mn2 < N))) return false;
	if(mx1 == mx2) return mn1 < mn2;
	else return mx1 < mx2;
}
 
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
 
	cin >> R >> C >> N;
	int Sr, Sc, Gr, Gc; cin >> Sr >> Sc >> Gr >> Gc; Sr--; Sc--; Gr--; Gc--;
	vector<string> v(R);
	for(auto &i : v) cin >> i;
	vector<pair<int, int>> added = {{Sr, Sc}};
	vector<vector<bool>> vis(R, vector<bool>(C, false));
	vector<vector<pair<int, int>>> best(R, vector<pair<int, int>>(C, {1e9, 1e9}));
	int d = 0;
	for(int t = 0; t < 2*R*C; t++){
		if(t==0){
			//Time to freely expand;
			queue<pair<int, int>> q;
			for(pair<int, int>& p : added){
				q.push(p);
			}
			while(!q.empty()){
				int i = q.front().first; int j = q.front().second; q.pop();
				if(i == Gr && j == Gc){
					cout << d << "\n";
					return 0;
				}
				// cout << "i " << i+1 << " j " << j+1 << " dist " << dist[i][j] << "\n";
				for(int ai = -1; ai <= 1; ai++){
					for(int aj = -1; aj <= 1; aj++){
						if(ai * aj != 0 || i + ai < 0 || i + ai >= R || j + aj < 0 || j + aj >= C) continue;
						int ni = i + ai; int nj = j + aj;
						// cout << "ni " << ni << " nj " << nj << "\n";
						if(v[ni][nj] == '.' && !vis[ni][nj]){
							added.push_back({ni, nj});
							q.push({ni, nj});
						}
					}
				}
			}
		}else{
			d++;
			priority_queue<tuple<int, int, int>> q;
			for(pair<int, int>& p : added){
				q.push({0, 0, p.first*C+p.second});
				best[p.first][p.second] = {0, 0};
				vis[p.first][p.second] = false;
			}
			added.clear();
			while(!q.empty()){
				int val = get<2>(q.top()); q.pop();
				int i = val/C; int j = val%C;
				if(i == Gr && j == Gc){
					cout << d << "\n";
					return 0;
				}
				if(vis[i][j]) continue;
				vis[i][j] = true;
				if(best[i][j].first >= N || best[i][j].second >= N){
					added.push_back({i, j});
				}
				for(int ai = -1; ai <= 1; ai++){
					for(int aj = -1; aj <= 1; aj++){
						if(ai * aj != 0 || i + ai < 0 || i + ai >= R || j + aj < 0 || j + aj >= C) continue;
						int ni = i + ai; int nj = j + aj;
						if(!vis[ni][nj] && isBest(best[i][j].first+abs(ai), best[i][j].second+abs(aj), best[ni][nj])){
							best[ni][nj] = {best[i][j].first+abs(ai), best[i][j].second+abs(aj)};
							q.push({-max(best[ni][nj].first, best[ni][nj].second), -min(best[ni][nj].first, best[ni][nj].second), ni*C+ nj});
						}else if(!vis[ni][nj] && v[ni][nj] == '.'){
							q.push({1e9, 1e9, ni*C+ nj});
						}
					}
				}
			}
		}
	}
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 19
• Subtask 3: 0 / 16
• Subtask 4: 0 / 19
• Subtask 5: 0 / 5
• Subtask 6: 0 / 19
• Subtask 7: 0 / 8
• Subtask 8: 0 / 6