-
Notifications
You must be signed in to change notification settings - Fork 1
/
LeetCode-36-Valid-Sudoku.java
54 lines (47 loc) · 1.71 KB
/
LeetCode-36-Valid-Sudoku.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
/*
LeetCode: https://leetcode.com/problems/valid-sudoku/
LintCode: http://www.lintcode.com/problem/valid-sudoku/
JiuZhang: http://www.jiuzhang.com/solutions/valid-sudoku/
ProgramCreek: http://www.programcreek.com/2014/05/leetcode-valid-sudoku-java/
Analysis:
1.Check each row
2.Check each column
3.Check each sub matrix
*/
public class Solution {
public boolean isValidSudoku(char[][] board) {
// check each row
for(int row = 0; row < 9; row++){
boolean[] checker = new boolean[9];
for(int col = 0; col < 9; col++){
if(board[row][col] != '.'){
if(checker[board[row][col] - '1']) return false;
checker[board[row][col] - '1'] = true;
}
}
}
// check each column
for(int col = 0; col < 9; col++){
boolean[] checker = new boolean[9];
for(int row = 0; row < 9; row++){
if(board[row][col] != '.'){
if(checker[board[row][col] - '1']) return false;
checker[board[row][col] - '1'] = true;
}
}
}
// check each sub matrix
for(int block = 0; block < 9; block++){
boolean[] checker = new boolean[9];
for(int row = block / 3 * 3; row < block / 3 * 3 + 3; row++){
for(int col = block % 3 * 3; col < block % 3 * 3 + 3; col++){
if(board[row][col] != '.'){
if(checker[board[row][col] - '1']) return false;
checker[board[row][col] - '1'] = true;
}
}
}
}
return true;
}
}