S.......#

#......S#

花费1，滑行

S.......#

#......S#

#S.....##

花费2，走旁边

#include<bits/stdc++.h>
using namespace std;
int n,m,p,sx,sy,ex,ey;
char a[1005][1005];
int b[4][1005][1005],dist[1005][1005],vis[1005][1005];
struct node{
	int x,y;
	bool operator < (const node &d) const {
		return dist[x][y] > dist[d.x][d.y];
	}
};
priority_queue<node> q;
int d[4][2]={{-1,0},{1,0},{0,1},{0,-1}};
int main(){
	freopen("Demarcation.in","r",stdin);
	freopen("Demarcation.out","w",stdout);
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++){
			cin>>a[i][j];
		}
	}
	cin>>sx>>sy>>ex>>ey;
	for(int j=1;j<=m;j++){
		p = 0;
		for(int i=1;i<=n;i++){
			if(a[i][j] == '#') p = i;
			else b[0][i][j] = p + 1;
		}
		p = 0;
		for(int i=n;i>=1;i--){
			if(a[i][j] == '#') p = i;
			else b[1][i][j] = p - 1;
		}
	}
	for(int i=1;i<=n;i++){
		p = 0;
		for(int j=1;j<=m;j++){
			if(a[i][j] == '#') p = j;
			else b[2][i][j] = p + 1;
		}
		p = 0;
		for(int j=m;j>=1;j--){
			if(a[i][j] == '#') p = j;
			else b[3][i][j] = p - 1;
		}
	}
	memset(dist,0x3f,sizeof(dist));
	dist[sx][sy] = 0;
	q.push((node){sx,sy});
	while(!q.empty()){
		node dt=q.top();
		q.pop();
		if(dt.x==ex && dt.y==ey){
			cout<<dist[dt.x][dt.y]<<endl;
			return 0;
		}
		if(vis[dt.x][dt.y]) continue;
		vis[dt.x][dt.y] = 1;
		int x=dt.x,y=dt.y;
		int de[4][2]={{b[0][x][y],dt.y},{b[1][x][y],dt.y},{dt.x,b[2][x][y]},{dt.x,b[3][x][y]}};
		for(int i=0;i<4;i++){
			int dx=de[i][0];
			int dy=de[i][1];
			if(dx<1 || dy<1 || dx>n || dy>m || a[dx][dy]=='#') continue;
			if(dist[dx][dy] > dist[dt.x][dt.y] + 1){
				dist[dx][dy] = dist[dt.x][dt.y] + 1;
				q.push((node){dx,dy});
			}
		}
		for(int i=0;i<4;i++){
			int dx=dt.x+d[i][0];
			int dy=dt.y+d[i][1];
			if(dx<1 || dy<1 || dx>n || dy>m || a[dx][dy]=='#') continue;
			if(dist[dx][dy] > dist[dt.x][dt.y] + 2){
				dist[dx][dy] = dist[dt.x][dt.y] + 2;
				q.push((node){dx,dy});
			}
		}
	}
	cout<<-1<<endl;
	return 0;
}