[leetcode]Valid Sudoku

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public class Solution { public boolean isValidSudoku(char[][] board) { if (board == null || board.length != 9 || board[0].length != 9) return false; boolean lookup[]; boolean lookCol[]; for (int i = 0; i < 9; i++){ lookup = new boolean[9]; lookCol = new boolean[9]; for (int j = 0; j < 9; j++){ if (board[i][j] != '.'){ int index = board[i][j] - '0'-1; if (lookup[index]) return false; lookup[index] = true; } if (board[j][i] != '.'){ int index2 = board[j][i] -'0'-1; if (lookCol[index2]) return false; lookCol[index2] = true; } } } for (int i = 0; i < 9; i+=3){ for (int j = 0; j < 9; j+=3){ lookup = new boolean[9]; lookCol = new boolean[9]; for (int k = i; k < i+3; k++){ for (int q = j; q < j+3; q++){ if (board[k][q] != '.'){ int index = board[k][q] - '0'-1; if (lookup[index]) return false; lookup[index] = true; } if (board[q][k] != '.'){ int index2 = board[q][k] -'0'-1; if (lookCol[index2]) return false; lookCol[index2] = true; } } } } } return true; } }