Valid Sudoku

http://blog.csdn.net/doc_sgl/article/details/13002461

rows[i][num]，cols[i][num]，blocks[i - i%3 + j/3][num]分别代表什么意思呢？

class Solution {public:    bool isValidSudoku(vector<vector<char> > &board) {        // Note: The Solution object is instantiated only once.vector<vector<bool>> rows(9, vector<bool>(9,false));vector<vector<bool>> cols(9, vector<bool>(9,false));vector<vector<bool>> blocks(9, vector<bool>(9,false));for(int i = 0; i < 9; i++)for(int j = 0; j < 9; j++){if(board[i][j] == '.')continue;int num = board[i][j] - '1';if(rows[i][num] || cols[j][num] || blocks[i - i%3 + j/3][num])return false;rows[i][num] = cols[j][num] = blocks[i - i%3 + j/3][num] = true;}return true;    }};