LeetCode 36 有效的数独

Posted 2021-12-17 Starzkg

https://leetcode-cn.com/problems/valid-sudoku/

解决方案

class Solution 
    public boolean isValidSudoku(char[][] board) 
        List<Set<Character>> list = new ArrayList<>();
        for (int i = 0; i < 27; i++) 
            list.add(new HashSet<>());
        
        for (int i = 0; i < 9; i++) 
            for (int j = 0; j < 9; j++) 
                if (board[i][j] == '.') 
                    continue;
                
                if (list.get(i).contains(board[i][j])) 
                    return false;
                
                list.get(i).add(board[i][j]);
                if (list.get(9 + j).contains(board[i][j])) 
                    return false;
                
                list.get(9 + j).add(board[i][j]);
                if (list.get(18 + i / 3 * 3 + j / 3).contains(board[i][j])) 
                    return false;
                
                list.get(18 + i / 3 * 3 + j / 3).add(board[i][j]);
            
        
        return true;