bzoj1193 [HNOI2006]马步距离

 1 //It is made by wfj_2048~
 2 #include <algorithm>
 3 #include <iostream>
 4 #include <cstring>
 5 #include <cstdlib>
 6 #include <cstdio>
 7 #include <vector>
 8 #include <cmath>
 9 #include <queue>
10 #include <stack>
11 #include <map>
12 #include <set>
13 #define inf (1<<30)
14 #define il inline
15 #define RG register
16 #define ll long long
17 #define File(s) freopen(s".in","r",stdin),freopen(s".out","w",stdout)
18 
19 using namespace std;
20 
21 const int d1[8]={1,2,1,2,-1,-2,-1,-2};
22 const int d2[8]={2,1,-2,-1,2,1,-2,-1};
23 
24 int qx[10010],qy[10010],dis[110][110],vis[110][110],x,y,sx,sy,tx,ty,ans;
25 
26 il int gi(){
27     RG int x=0,q=1; RG char ch=getchar();
28     while ((ch<‘0‘ || ch>‘9‘) && ch!=‘-‘) ch=getchar();
29     if (ch==‘-‘) q=-1,ch=getchar();
30     while (ch>=‘0‘ && ch<=‘9‘) x=x*10+ch-48,ch=getchar();
31     return q*x;
32 }
33 
34 il void bfs(){
35     RG int h=0,t=1; qx[t]=x,qy[t]=y;
36     while (h<t){
37     RG int xx=qx[++h],yy=qy[h],XX,YY;
38     for (RG int i=0;i<8;++i){
39         XX=xx+d1[i],YY=yy+d2[i];
40         if (XX<0 || XX>100 || YY<0 || YY>100 || vis[XX][YY]) continue;
41         dis[XX][YY]=dis[xx][yy]+1,qx[++t]=XX,qy[t]=YY;
42         vis[XX][YY]=1; if (XX==50 && YY==50) return;
43     }
44     }
45     return;
46 }
47 
48 il void work(){
49     sx=gi(),sy=gi(),tx=gi(),ty=gi(),x=abs(sx-tx),y=abs(sy-ty);
50     while (x+y>=50){
51     if (x<y) swap(x,y); ans+=2;
52     if (x-4>=2*y) x-=4; else x-=4,y-=2;
53     }
54     x+=50,y+=50,bfs(); printf("%d\n",ans+dis[50][50]); return;
55 }
56 
57 int main(){
58     File("horse");
59     work();
60     return 0;
61 }