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飞过闲红千叶，夕岸在哪
类目归类
[LeetCode 36] Valid Sudoku [Java]
01/19
1. Description
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 '.'.
Note: A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.
2. Code
import java.util.HashSet;
import java.util.Set;
public class LeetCode0036 {
public boolean isValidSudoku(char[][] board) {
if (board == null || board.length != 9 || board[0] == null || board[0].length != 9) {
return false;
}
Set[][] block = new HashSet[3][3];
for (int i = 0; i < 9; i++) {
Set row = new HashSet();
Set col = new HashSet();
for (int j = 0; j < 9; j++) {
if (board[j][i] != '.' && !col.add(board[j][i])) {
return false;
}
if (board[i][j] == '.') {
continue;
}
if (!row.add(board[i][j])) {
return false;
}
if (block[i / 3][j / 3] == null) {
block[i / 3][j / 3] = new HashSet();
}
if (!block[i / 3][j / 3].add(board[i][j])) {
return false;
}
}
}
return true;
}
public static void main(String[] args) {
LeetCode0036 leetcode = new LeetCode0036();
System.out.println(leetcode.isValidSudoku(new char[][] { { '.', '8', '7', '6', '5', '4', '3', '2', '1' },
{ '2', '.', '.', '.', '.', '.', '.', '.', '.' }, { '3', '.', '.', '.', '.', '.', '.', '.', '.' },
{ '4', '.', '.', '.', '.', '.', '.', '.', '.' }, { '5', '.', '.', '.', '.', '.', '.', '.', '.' },
{ '6', '.', '.', '.', '.', '.', '.', '.', '.' }, { '7', '.', '.', '.', '.', '.', '.', '.', '.' },
{ '8', '.', '.', '.', '.', '.', '.', '.', '.' }, { '9', '.', '.', '.', '.', '.', '.', '.', '.' } }));
}
}
