1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 #include<iostream>
 5 #include<string>
 6 #include<vector>
 7 #include<stack>
 8 #include<bitset>
 9 #include<cstdlib>
10 #include<cmath>
11 #include<set>
12 #include<list>
13 #include<deque>
14 #include<map>
15 #include<queue>
16 #define ll long long
17 #define inf 0x3fffffff
18 using namespace std;
19 struct Node
20 {
21     int x,y,step;
22 };
23 queue<Node> q;
24 int n,m;
25 int a[25][25];
26 int vis[25][25];
27 int d[][2]={{1,2},{1,-2},{-1,2},{-1,-2},{2,1},{2,-1},{-2,1},{-2,-1}};
28
29 bool check(int x,int y)
30 {
31     if(x<0||x>=n||y<0||y>=m)
32         return false;
33     if(vis[x][y])
34         return false;
35     return true;
36 }
37 int bfs(int x1,int y1,int x2,int y2)
38 {
39     memset(vis,0,sizeof(vis));
40     q.push( (Node){x1,y1,0} );
41     vis[x1][y1]=1;
42     while(!q.empty())
43     {
44         Node u=q.front();
45         q.pop();
46         if(u.x==x2&&u.y==y2)//到达目标
47         {
48             return u.step;
49         }
50         for(int i=0;i<8;i++)//遍历八个方向
51         {
52              int x=u.x+d[i][0];
53              int y=u.y+d[i][1];
54              if(check(x,y))//检查边界
55              {
56                  vis[x][y]=1;
57                  q.push(Node{x,y,u.step+1});//步数加1
58              }
59         }
60     }
61     return -1;//如果不能吃掉将则输出“-1”
62 }
63
64 int main()
65 {
66     int x1,y1,x2,y2;
67     while(~scanf("%d%d%d%d%d%d",&n,&m,&x1,&y1,&x2,&y2))
68     {
69         memset(vis,0,sizeof(vis));
70        int ans= bfs(x2,y2,x1,y1);
71         printf("%d\n",ans);
72     }
73     return 0;
74 }