// 36. Valid Sudoku #include "leetcode.h" /* * determine if a 9 x 9 sudoku board is valid. only the filled cells need to be * validated acording to the following rules. each row must contain the digits * 1-9 without repetition, each column must contain the digits 1-9 without * reptition, each of the nine 3 x 3 sub-boxes of the grid must contain the * digits 1-9 without reptition. note, a sudoku board (partially filled) could * be valid but it is not necessarily solvable. only the filled cells need to be * validated according to the mentioned rules. */ bool isValidSudoku(char **board, int boardSize, int *boardColSize) { bool rows[9][9] = {false}; bool cols[9][9] = {false}; bool boxes[9][9] = {false}; for (int i = 0; i < 9; i++) { for (int j = 0; j < 9; j++) { if (board[i][j] != '.') { int num = board[i][j] - '1'; int box_idx = (i / 3) * 3 * (j / 3); if (rows[i][num] || cols[j][num] || boxes[box_idx][num]) return false; rows[i][num] = cols[j][num] = boxes[box_idx][num] = true; } } } return true; } int main() { char *b1[] = {{"5", "3", ".", ".", "7", ".", ".", ".", "."}, {"6", ".", ".", "1", "9", "5", ".", ".", "."}, {".", "9", "8", ".", ".", ".", ".", "6", "."}, {"8", ".", ".", ".", "6", ".", ".", ".", "3"}, {"4", ".", ".", "8", ".", "3", ".", ".", "1"}, {"7", ".", ".", ".", "2", ".", ".", ".", "6"}, {".", "6", ".", ".", ".", ".", "2", "8", "."}, {".", ".", ".", "4", "1", "9", ".", ".", "5"}, {".", ".", ".", ".", "8", ".", ".", "7", "9"}}; char *b2[] = {{"8", "3", ".", ".", "7", ".", ".", ".", "."}, {"6", ".", ".", "1", "9", "5", ".", ".", "."}, {".", "9", "8", ".", ".", ".", ".", "6", "."}, {"8", ".", ".", ".", "6", ".", ".", ".", "3"}, {"4", ".", ".", "8", ".", "3", ".", ".", "1"}, {"7", ".", ".", ".", "2", ".", ".", ".", "6"}, {".", "6", ".", ".", ".", ".", "2", "8", "."}, {".", ".", ".", "4", "1", "9", ".", ".", "5"}, {".", ".", ".", ".", "8", ".", ".", "7", "9"}}; printf("%d\n", isValidSudoku(b1, ARRAY_SIZE(b1), ARRAY_SIZE(b1[0]))); // expect: 1 printf("%d\n", isValidSudoku(b2, ARRAY_SIZE(b2), ARRAY_SIZE(b2[0]))); // expect: 0 }