有关数独问题的解决方法- Java实现

直接法和位运算发

 1 public boolean isValidSudoku(char[][] board) {
 2     int[][] line=new int[board.length][board.length];
 3     int[][] colum=new int[board.length][board.length];
 4     int[][] cell=new int[board.length][board.length];
 5     for (int i = 0; i < board.length; i++) {
 6         for (int j = 0; j < board.length; j++) {
 7             if (board[i][j]=='.')
 8                 continue;
 9             int num=board[i][j]-'0'-1;
10             int k=i/3*3+j/3;
11             if (line[i][num]!=0||colum[num][j]!=0||cell[k][num]!=0)
12                 return false;
13             line[i][num]=colum[num][j]=cell[k][num]=1;
14         }
15     }
16     return true;
17 }
18 public boolean isValidSudoku2(char[][] board) {
19     int[] line=new int[board.length];
20     int[] colum=new int[board.length];
21     int[] cell=new int[board.length];
22     int numsBits=0;
23     for (int i = 0; i < board.length; i++) {
24         for (int j = 0; j < board.length; j++) {
25             if (board[i][j]=='.')
26                 continue;
27             numsBits=1<<(board[i][j]-'0');
28             int k=i/3*3+j/3;
29             if ((line[i]&numsBits)>0||(colum[j]&numsBits)>0||(cell[k]&numsBits)>0)
30                 return false;
31             //此时的表示的每一行是否重复
32             line[i]|=numsBits;
33             colum[j]|=numsBits;
34             cell[k]|=numsBits;
35 
36         }
37     }
38     return true;
39 }