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authorJack Sangdahl <[email protected]>2025-08-29 22:19:11 -0600
committerJack Sangdahl <[email protected]>2025-08-29 22:19:11 -0600
commit9bdedfa9d768668c571d721d0b7a30f0eae1b58c (patch)
treea6ff6c39bbe88d96d543bd4a61b31d79edf31f77
parente8c2d0bdc53d995966742df427a3ddd021ee3644 (diff)
downloadleetcode-master.tar.gz
leetcode-master.zip
36. valid sudokuHEADmaster
-rw-r--r--valid_sudoku.c55
-rw-r--r--valid_sudoku.py59
2 files changed, 114 insertions, 0 deletions
diff --git a/valid_sudoku.c b/valid_sudoku.c
new file mode 100644
index 0000000..dd93f60
--- /dev/null
+++ b/valid_sudoku.c
@@ -0,0 +1,55 @@
+// 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
+}
diff --git a/valid_sudoku.py b/valid_sudoku.py
new file mode 100644
index 0000000..8dd758a
--- /dev/null
+++ b/valid_sudoku.py
@@ -0,0 +1,59 @@
+# 36. Valid Sudoku
+
+"""
+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.
+"""
+
+
+class Solution(object):
+ def isValidSudoku(self, board):
+ """
+ :type board: List[List[str]]
+ :rtype: bool
+ """
+ rows = [[False] * 9 for _ in range(9)]
+ cols = [[False] * 9 for _ in range(9)]
+ boxes = [[False] * 9 for _ in range(9)]
+ for i in range(9):
+ for j in range(9):
+ if board[i][j] != ".":
+ num = ord(board[i][j] - ord("1"))
+ box_idx = (i // 3) * 3 + (j // 3)
+ if rows[i][num] or cols[j][num] or boxes[box_idx][num]:
+ return False
+ rows[i][num] = cols[j][num] = boxes[box_idx][num] = True
+ return True
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ 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"],
+ ]
+ 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"],
+ ]
+ print(obj.isValidSudoku(b1))
+ print(obj.isValidSudoku(b2))