leetcode -- Valid Sudoku

Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.

The Sudoku board could be partially filled, where empty cells are filled with the character '.'.

A partially filled sudoku which is valid.

判断数独是否合法：

1. 同一行中1-9出现次数不重复

2. 同一列中1-9出现次数不重复

3. 9宫格中1-9出现次数不重复

 

这里将1,2的判断在一个循环体中进行，分开进行跑大数据集时会TLE

 1 public boolean isValidSudoku(char[][] board) {
 2         // Start typing your Java solution below
 3         // DO NOT write main() function
 4         if(board.length == 0)
 5             return false;
 6         
 7         for(int i = 0; i < 9; i++){
 8             Set<Character> row = new HashSet<Character>();
 9             Set<Character> col = new HashSet<Character>();
10             for(int j = 0; j < 9; j++){
11                 if(board[i][j] != '.'){
12                     if(row.contains(board[i][j]))
13                         return false;
14                     else {
15                         row.add(board[i][j]);
16                     }
17                 }
18                 
19                 if(board[j][i] != '.'){
20                     if(col.contains(board[j][i]))
21                         return false;
22                     else
23                         col.add(board[j][i]);
24                 }
25                 
26             }
27         }
28         
29         for(int i = 0; i < 9; i+=3){
30             for(int j = 0; j < 9; j+=3){
31                 Set<Character> container = new HashSet<Character>();
32                 for(int m = 0; m < 3; m++){
33                     for(int n = 0; n < 3; n++){
34                         if(board[m + i][n + j] == '.'){
35                             continue;
36                         }
37                         if(container.contains(board[m + i][n + j]))
38                             return false;
39                         else {
40                             container.add(board[m + i][n + j]);
41                         }
42                     }
43                         
44                 }
45                 container.clear();
46             }
47         }
48         return true;
49         
50     }