Leetcode 36.Valid Sudoku

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.

Note:
A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.

s思路：
1. sudoku判断。行、列、小方块分别判断。对行来说，每一行都判断有没有重复的数字，一般而言，用hash就可以判断，但这里数字都是有限范围的，直接用vector< bool>(9,0)来判断即可！
2. 为了省空间，可以只用一个vector< bool>(9,0)，每行判断完即可清零重新写；另一种就是用vector

class Solution {public:    bool isValidSudoku(vector<vector<char>>& board) {        //        vector<vector<bool>> row(9,vector<bool>(10,0));        vector<vector<bool>> col(9,vector<bool>(10,0));        vector<vector<bool>> block(9,vector<bool>(10,0));        for(int i=0;i<9;i++){            for(int j=0;j<9;j++){                if(board[i][j]=='.') continue;                int cur=board[i][j]-'0';                int idx=i/3*3+j/3;//这里有一个可爱的bug:3*i/3就错误，需要3*(i/3)!                if(row[i][cur]||col[j][cur]||block[idx][cur])                       return false;                row[i][cur]=1;                col[j][cur]=1;                block[idx][cur]=1;            }            }        return true;    }