有效的数独

题目链接

有效的数独

题目描述

注意点

board.length == 9
board[i].length == 9
board[i][j] 是一位数字（1-9）或者 ‘.’

解答思路

首先判断行是否满足数独条件，再判断列是否满足数独条件，最后再判断划分的3x3方格是否满足数独条件，中间有一处不满足则直接返回false，遍历完后都满足条件则返回true

代码

class Solution {public boolean isValidSudoku(char[][] board) {int row = board.length;int col = board[0].length;// 判断行for (int i = 0; i < row; i++) {int[] arr = new int[10];for (int j = 0; j < col; j++) {if (board[i][j] == '.') {continue;}if (arr[board[i][j] - '0'] != 0) {return false;}arr[board[i][j] - '0'] = 1;}}// 判断列for (int j = 0; j < col; j++) {int[] arr = new int[10];for (int i = 0; i < row; i++) {if (board[i][j] == '.') {continue;}if (arr[board[i][j] - '0'] != 0) {return false;}arr[board[i][j] - '0'] = 1;}}// 判断3 x 3方格for (int i = 0; i < row; i = i + 3) {for (int j = 0; j < col; j = j + 3) {if (!isValidSudokuSquare(board, i, j)) {return false;}}}return true;}public boolean isValidSudokuSquare(char[][] board, int x, int y) {int[] arr = new int[10];for (int i = 0; i < 3; i++) {for (int j = 0; j < 3; j++) {if (board[x + i][y + j] == '.') {continue;}if (arr[board[x + i][y + j] - '0'] != 0) {return false;}arr[board[x + i][y + j] - '0'] = 1; }}return true;}
}