[LeetCode] Valid Sudoku

问题：

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 '.'.

A partially filled sudoku which is valid.

分析：

先分析行；再分析列；最后分析九宫格。前两个都好说，第三个要注意index。

代码：

class Solution {public:bool isValidSudoku(vector<vector<char> > &board) {// rowfor (int i = 0; i < 9; i ++) {vector<bool> numbers (9, false);for (int j = 0; j < 9; j ++) {char c = board[i][j];if (c == '.') continue;if (numbers[c - '0' - 1] == true)return false;elsenumbers[c - '0' - 1] = true;}}// colfor (int i = 0; i < 9; i ++) {vector<bool> numbers(9, false);for (int j = 0; j < 9; j ++) {char c = board[j][i];if (c == '.') continue;if (numbers[c - '0' - 1] == true)return false;elsenumbers[c - '0' - 1] = true;}}// ninesfor (int i = 0; i < 9; i ++) {vector<bool> numbers(9, false);for (int j = 0; j < 9; j ++) {int a = 3 * (i / 3) + j / 3; // rowint b = (j % 3) + (i % 3) * 3; // colchar c = board[a][b];if (c == '.') continue;if (numbers[c - '0' - 1] == true)return false;elsenumbers[c - '0' - 1] = true;}}return true;}};