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// 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
}
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