C++ :

#include<stdio.h>
#include<queue>
using namespace std;
struct node
{
	int x,y;
};

int main()
{
	int n;
	while(scanf("%d",&n)!=EOF)
	{
		char a[1000][1000];
		int bb[1000][1000];
		getchar();
		queue<node>q;
		for (int i=0;i<n;i++)
		{
			scanf("%s",a[i]);
			getchar();
		}
		node as,ab;
		scanf("%d%d",&as.x,&as.y);
		as.x--;as.y--;
		scanf("%d%d",&ab.x,&ab.y);
		ab.x--;ab.y--;
		a[as.x][as.y]='1';
		q.push(as);int all=0;
		bb[as.x][as.y]=0;
		while(!q.empty())
		{
			if (q.front().x==ab.x&&q.front().y==ab.y) {break;}
			else 
			{
				node ww;
				all=bb[q.front().x][q.front().y];
				if (q.front().x-1>=0&&a[q.front().x-1][q.front().y]=='0')  {bb[q.front().x-1][q.front().y]=all+1;a[q.front().x-1][q.front().y]='1';ww.x=q.front().x-1;ww.y=q.front().y;q.push(ww);}
				if (q.front().y-1>=0&&a[q.front().x][q.front().y-1]=='0')  {bb[q.front().x][q.front().y-1]=all+1;a[q.front().x][q.front().y-1]='1';ww.x=q.front().x;ww.y=q.front().y-1;q.push(ww);}
				if (q.front().y+1<=n-1&&a[q.front().x][q.front().y+1]=='0')  {bb[q.front().x][q.front().y+1]=all+1;a[q.front().x][q.front().y+1]='1';ww.x=q.front().x;ww.y=q.front().y+1;q.push(ww);}
				if (q.front().x+1<=n-1&&a[q.front().x+1][q.front().y]=='0')  {bb[q.front().x+1][q.front().y]=all+1;a[q.front().x+1][q.front().y]='1';ww.x=q.front().x+1;ww.y=q.front().y;q.push(ww);}
			}
			q.pop();
		}
		printf("%d\n",bb[ab.x][ab.y]);
	}
	return 0;
}