#include<stdio.h>
struct note
{
int x;
int y;
int f;
int s;
};
int main()
{
struct note que[2501];
int a[51][51]={0},book[51][51]={0};
int next[4][2]={{0,1},{1,0},{0,-1},{-1,0}
};
int head,tail;
int i,j,k,n,m,startx,starty,p,q,tx,ty,flag;
scanf("%d %d",&n,&m);
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
scanf("%d",&a[j]);
scanf("%d %d %d %d",&startx,&starty,&p,&q);
head=1;tail=1;
que[tail].x=startx;que[tail].y=starty;
que[tail].s=0;tail++;
book[startx][starty]=1;
flag=0;
while(head<tail)
{
for(k=0;k<=3;k++)
{
tx=que[head].x+next[k][0];
ty=que[head].y+next[k][1];
if(tx<1 || tx>n ||ty<1 ||ty>m)
continue;
if(a[tx][ty]==0&&book[tx][ty])
{
book[tx][ty]=1;
que[tail].x=tx;
que[tail].y=ty;
que[tail].s=que[head].s+1;
tail++;
}
if(tx==p && ty==q)
{
flag=1;break;
}
}
if(flag==1)
break;
head++;
}
printf("%d",que[tail-1].s);
return 0;
}
请问怎么回事
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