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.
分析
就是对横向,纵向,以及子方格进行验证,保证出现的1-9这些数字没有重复;
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | class Solution { public : bool isValidSudoku(vector<vector< char >>& board) { bool rv[9][9] = { false }, cv[9][9] = { false }, sv[9][9] = { false }; for ( int i = 0; i < 9; ++i){ for ( int j = 0; j < 9; ++j){ if (board[i][j] != '.' ){ int p = board[i][j] - '0' - 1, k = i/3 * 3 + j/3; if (rv[i][p] || cv[p][j] || sv[k][p]){ return false ; } rv[i][p] = cv[p][j] = sv[k][p] = true ; } } } return true ; } }; |