Submission #1093783

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093783		Abito	Maze (JOI23_ho_t3)	C++17	67 / 100	651 ms	195448 KiB

Main

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define ep insert
#define endl '\n'
#define elif else if
#define pow pwr
#define sqrt sqrtt
#define int long long
#define ll long long
typedef unsigned long long ull;
using namespace std;
const int N=400,M=2e5;
int n,m,k,sx,sy,ex,ey,mvx[]={1,0,-1,0},mvy[]={0,1,0,-1};
vector<vector<int>> dis,p;
vector<vector<bool>> vis;
vector<vector<char>> a;
bool ok(int x,int y){
	return x>=1 && x<=n && y>=1 && y<=m && a[x][y]=='.'; 
}
void bfs1(){
	deque<pair<int,int>> dq;
	dq.push_front({sx,sy});
	dis[sx][sy]=0;
	while (!dq.empty()){
		int x=dq.front().F,y=dq.front().S;
		dq.pop_front();
		if (vis[x][y]) continue;
		//cout<<x<<' '<<y<<' '<<dis[x][y]<<endl;
		vis[x][y]=1;
		for (int i=0;i<4;i++){
			int nx=mvx[i]+x,ny=mvy[i]+y;
			if (!ok(nx,ny)) continue;
			if (dis[nx][ny]>dis[x][y]){
				dis[nx][ny]=dis[x][y];
				dq.push_front({nx,ny});
			}
		}
		for (int i=max(1LL,x-k);i<=min(n,x+k);i++){
			for (int j=max(1LL,y-k);j<=min(m,y+k);j++){
				if (i==x-k && j==y-k) continue;
				if (i==x-k && j==y+k) continue;
				if (i==x+k && j==y-k) continue;
				if (i==x+k && j==y+k) continue;
				if (dis[i][j]>dis[x][y]+1){
					dis[i][j]=dis[x][y]+1;
					dq.push_back({i,j});
				}
			}
		}
	}
	return;
}
void bfs2(){
	vector<pair<int,int>> q;
	dis[sx][sy]=0;
	vis[sx][sy]=1;
	q.pb({sx,sy});
	for (int t=0;t<INT_MAX;t++){
		for (int i=0;i<q.size();i++){
			int x=q[i].F,y=q[i].S;
			dis[x][y]=t;
			for (int j=0;j<4;j++){
				int nx=x+mvx[j],ny=y+mvy[j];
				if (vis[nx][ny] || !ok(nx,ny)) continue;
				dis[nx][ny]=t;
				vis[nx][ny]=1;
				q.pb({nx,ny});
			}
		}
		//for (auto u:q) cout<<u.F<<' '<<u.S<<"	";
		//cout<<endl;
		if (vis[ex][ey]) break;
		for (int i=0;i<=n+5;i++) for (int j=0;j<=m+5;j++) p[i][j]=0;
		for (int i=0;i<q.size();i++){
			int x=q[i].F,y=q[i].S;
			p[max(1LL,x-k)][max(1LL,y-k)]++;
			p[max(1LL,x-k)][min(m,y+k)+1]--;
			p[min(n,x+k)+1][max(1LL,y-k)]--;
			p[min(n,x+k)+1][min(m,y+k)+1]--;
			if (x-k>=1 && y-k>=1){
				p[x-k][y-k]--;
				p[x-k+1][y-k]++;
				p[x-k][y-k+1]++;
				p[x-k+1][y-k+1]--;
			}
			if (x-k>=1 && y+k<=m){
				p[x-k][y+k]--;
				p[x-k+1][y+k]++;
				p[x-k][y+k+1]++;
				p[x-k+1][y+k+1]--;
			}
			if (x+k<=n && y-k>=1){
				p[x+k][y-k]--;
				p[x+k+1][y-k]++;
				p[x+k][y-k+1]++;
				p[x+k+1][y-k+1]--;
			}
			if (x+k<=n && y+k<=m){
				p[x+k][y+k]--;
				p[x+k+1][y+k]++;
				p[x+k][y+k+1]++;
				p[x+k+1][y+k+1]--;
			}
		}
		for (int i=1;i<=n;i++){
			for (int j=1;j<=m;j++){
				p[i][j]+=p[i-1][j]+p[i][j-1]-p[i-1][j-1];
				if (p[i][j]>0 && !vis[i][j]) q.pb({i,j}),vis[i][j]=1;
				//cout<<p[i][j]<<' ';
			}//cout<<endl;
		}//cout<<endl;
	}
}
int32_t main(){
	ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	cin>>n>>m>>k>>sx>>sy>>ex>>ey;
	for (int i=0;i<=n+5;i++){
		p.pb({});dis.pb({});vis.pb({});a.pb({});
		for (int j=0;j<=m+5;j++){
			p[i].pb(0);dis[i].pb(INT_MAX);vis[i].pb(0);a[i].pb('#');
		}
	}
	for (int i=1;i<=n;i++) for (int j=1;j<=m;j++) cin>>a[i][j];
	if ((2*k+1)*(2*k+1)<=N) bfs1();
	else bfs2();
	cout<<dis[ex][ey]<<endl;
	return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void bfs2()':
Main.cpp:63:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |   for (int i=0;i<q.size();i++){
      |                ~^~~~~~~~~
Main.cpp:78:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |   for (int i=0;i<q.size();i++){
      |                ~^~~~~~~~~

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