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leetcode no 36 valid sudoku

admin 11月 11, 2020 0

1. 题目

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. 思路

根据数独游戏的规则，一个9行9列的棋盘，每行每列和每一个3*3的小方格都不能有重复的数字，并且数字只能是0-9，逐一判断这些规则是否满足即可

public class  {
    	public boolean isValidSudoku(char[][] board) { 
		if(board.length != 9 || board[0].length != 9){
			return false;
		}
		for(int i=0;i<9;i++){
			int[] map = new int[10];
			for(int j=0;j<9;j++){
				if(board[i][j] == '.')continue;
				int num = board[i][j]-'0';
				if(map[num] == 1){
					return false;
				}
				map[num] = 1;
			}
		}
		for(int j=0;j<9;j++){
			int[] map = new int[10];
			for(int i=0;i<9;i++){
				if(board[i][j] == '.')continue;
				int num = board[i][j]-'0';
				if(map[num] == 1){
					return false;
				}
				map[num] = 1;
			}
		}
		for(int i=0;i<9;i+=3){
			for(int j=0;j<9;j+=3){
				int[] map = new int[10];
				for(int k=i;k<i+3;k++){
					for(int l=j;l<j+3;l++){
						if(board[k][l] == '.')continue;
						int num = board[k][l]-'0';
						if(map[num] == 1){
							return false;
						}
						map[num] = 1;
					}
				}
			}
		}
		return true;
	}
}