1 #include<iostream>
2 #include<cstring>
3 #define max 1000000
4 using namespace std;
5 const int dir[4][2]={{1,0},{0,1},{-1,0},{0,-1}};
6 string origion;
7 string goal;
8 string state[max];
9 int vis[370000];
10
11 bool encode(string str){ //康拖展开 编码
12 int x=1,sum=0,n=8;
13 for(int i=1;i<9;i++){
14 x=i*x;
15 }
16 for( int i=0 ; i < str.length() ; i++){
17 if( str[i]<='9' && str[i]>='0' ){
18 int cnt=0;
19 for(int j=i+1 ; j<str.length() ; j++){
20 if(str[j]!=' '&& str[j] < str[i]){
21 cnt++;
22 }
23 }
24 sum+=cnt*x;
25 if(x!=1)
26 x=x/n;
27 n--;
28 }
29 }
30 if(vis[sum]){
31 vis[sum]=0;
32 return true;
33 }
34 return false;
35 }
36 int bfs(){
37 state[0]=origion;
38 encode(origion);
39 int front=0,rear=1;
40 int floor=0,amt=1;
41 int temp=0;
42
43 while(front!=rear){
44 string str1=state[front],str2=str1;
45 front=(front+1)%max;
46
47 if(amt==0){
48 amt=temp;
49 temp=0;
50 floor++;
51 }
52 if(str1==goal){
53 return floor;
54 }
55 int pos=0,i,j;
56 while(pos<str1.length()){
57 if(str1[pos]=='0') break;
58 pos++;
59 }
60 i=pos/6;
61 j=(pos/2)%3;
62
63 for(int k=0;k<4;k++){
64 str1=str2;
65 int x=i+dir[k][0];
66 int y=j+dir[k][1];
67
68 if(x>=0&&x<3&&y>=0&&y<3){
69 char t=str1[pos];
70 str1[pos]=str1[x*6+y*2];
71 str1[x*6+y*2]=t;
72
73 if(encode(str1)){
74 if( (rear+1)%max == front)
75 return -1;
76 state[rear]=str1;
77 rear = (rear+1)%max;
78 temp++;
79 }
80
81 }
82 }
83 amt--;
84 }
85 return 0;
86 }
87 int main(){
88 while( getline(cin,origion) && getline(cin,goal)){
89 memset(vis,-1,sizeof(vis));
90 cout<<bfs()<<endl;
91 }
92 }
93 /*
94 2 6 4 1 3 7 0 5 8
95 8 1 5 7 3 6 4 0 2
96 */
