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//第一次在新博客里發文章好緊張怎么辦
//MD巨神早已在一個小時前做完了
The Rotation Game
| Time Limit: 15000MS | Memory Limit: 150000K | |
| Total Submissions: 5950 | Accepted: 1992 |
Description
The rotation game uses a # shaped board, which can hold 24 pieces of square blocks (see Fig.1). The blocks are marked with symbols 1, 2 and 3, with exactly 8 pieces of each kind.
Initially, the blocks are placed on the board randomly. Your task is to move the blocks so that the eight blocks placed in the center square have the same symbol marked. There is only one type of valid move, which is to rotate one of the four lines, each consisting of seven blocks. That is, six blocks in the line are moved towards the head by one block and the head block is moved to the end of the line. The eight possible moves are marked with capital letters A to H. Figure 1 illustrates two consecutive moves, move A and move C from some initial configuration.
Initially, the blocks are placed on the board randomly. Your task is to move the blocks so that the eight blocks placed in the center square have the same symbol marked. There is only one type of valid move, which is to rotate one of the four lines, each consisting of seven blocks. That is, six blocks in the line are moved towards the head by one block and the head block is moved to the end of the line. The eight possible moves are marked with capital letters A to H. Figure 1 illustrates two consecutive moves, move A and move C from some initial configuration.
Input
The input consists of no more than 30 test cases. Each test case has only one line that contains 24 numbers, which are the symbols of the blocks in the initial configuration. The rows of blocks are listed from top to bottom. For each row the blocks are listed from left to right. The numbers are separated by spaces. For example, the first test case in the sample input corresponds to the initial configuration in Fig.1. There are no blank lines between cases. There is a line containing a single `0' after the last test case that ends the input.
Output
For each test case, you must output two lines. The first line contains all the moves needed to reach the final configuration. Each move is a letter, ranging from `A' to `H', and there should not be any spaces between the letters in the line. If no moves are needed, output `No moves needed' instead. In the second line, you must output the symbol of the blocks in the center square after these moves. If there are several possible solutions, you must output the one that uses the least number of moves. If there is still more than one possible solution, you must output the solution that is smallest in dictionary order for the letters of the moves. There is no need to output blank lines between cases.
Sample Input
1 1 1 1 3 2 3 2 3 1 3 2 2 3 1 2 2 2 3 1 2 1 3 3
1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3
0
Sample Output
AC
2
DDHH
2
------------------------------------------------------------------------------------------------------
poj英文題的尿性呵呵噠
大概就是把那個棋盤的abcdef軸旋轉次數最少使得中間那幾個數字相同（注意只有1,2,3）
那么先找規律，就是把輸入數據的位置與abcdef對應
接下來因為搜索層數未知，dfs會TLE，bfs會MLE，所以容易想到ID搜索
先指定遞歸層數，然后迭代加深一層一層搜下去（有的說用二分但這種小數據反而更費時）
再看每一層的搜索方向
聯想八數碼問題（然而并不清楚八數碼問題），發現每個狀態都有最多遞歸的層數（八個位置貪心減去目前最多的數字個數）
那么寫一個估價函數猜猜最多搜多少，如果超出了層數限制那就剪枝，這樣就有了IDA*
（我在說些什么）
代碼代碼代碼我要去睡
1 #include<stdio.h>
2 #include<stdlib.h>
3 #include<string.h>
4 #include<limits.h>
5 int min(int a,int b){
6 return a<b?a:b;
7 }
8 int lines[10][10]={
9 { 0, 2, 6,11,15,20,22},// A
10 { 1, 3, 8,12,17,21,23},// B
11 {10, 9, 8, 7, 6, 5, 4},// C
12 {19,18,17,16,15,14,13},// D
13 {23,21,17,12, 8, 3, 1},//E
14 {22,20,15,11, 6, 2, 0},//F
15 {13,14,15,16,17,18,19},//G
16 { 4, 5, 6, 7, 8, 9,10},//H
17 };
18 int matrix[10]={6,7,8,11,12,15,16,17};
19 int cross[30];
20 char ans[100];
21 int check(){
22 for(int i=0;i<8;i++)if(cross[matrix[0]]!=cross[matrix[i]])return 0;
23 return 1;
24 }
25 int predict(){
26 int most=100;
27 for(int i=1;i<=3;i++){
28 int a=0;
29 for(int j=0;j<8;j++)if(cross[matrix[j]]!=i)a++;
30 most=min(most,a);
31 }
32 return most;
33 }
34 int rotate(int mode){
35 int le=cross[lines[mode][0]];
36 for(int i=0;i<6;i++)cross[lines[mode][i]]=cross[lines[mode][i+1]];
37 cross[lines[mode][6]]=le;
38 return 0;
39 }
40 int dfs(int dpt,int dptm){
41 if(dpt==dptm) return check();
42 if(dpt+predict()>dptm) return 0;
43 for(int i=0;i<8;i++){
44 ans[dpt]=i+'A';
45 rotate(i);
46 if(dfs(dpt+1,dptm)) return 1;
47 if(i%2==0) rotate((i+5)%8);
48 else rotate((i+3)%8);
49 }
50 return 0;
51 }
52 int main(){
53 while(scanf("%d",&cross[0])!=EOF&&cross[0]!=0){
54 for(int i=1;i<24;i++) scanf("%d",&cross[i]);
55 if(check()) printf("No moves needed\n");
56 else{
57 int i=0;
58 while(++i) if(dfs(0,i)) break;
59 ans[i]='\0';
60 printf("%s\n",ans);
61 }
62 printf("%d\n",cross[matrix[0]]);
63 }
64 return 0;
65 }
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