is sudoku valid problem

Author: Ikboljon Abdurasulov

Python/20days_marathon/9_day/isValidSudoku.py

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+# LINK: https://leetcode.com/problems/group-anagrams/
+# COMPLEXITY: Time complexity: O(1) Space complexity: O(1)
+#Explanation:  Since the size of the input board is fixed at 9x9, 
+#   the number of iterations in the two loops is constant, which 
+#   means the time complexity is constant. Similarly, the size of the 
+#   data structures used to keep track of the numbers is also fixed at
+#   9x9, which means the space complexity is also constant.
+import collections
+class Solution:
+    def isValidSudoku(self, board):
+        cols = collections.defaultdict(set)
+        rows = collections.defaultdict(set)
+        squares = collections.defaultdict(set)
+
+        for r in range(9):
+            for c in range(9):
+                if board[r][c] == '.':
+                    continue
+                if (board[r][c] in rows[r] or 
+                    board[r][c] in cols[c]or 
+                    board[r][c] in squares[(r//3,c//3)]):
+                    return False
+                cols[c].add(board[r][c])
+                rows[r].add(board[r][c])
+                squares[(r//3,c//3)].add(board[r][c])
+        return True

Python/20days_marathon/9_day/test_isValidSudoku.py

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+import pytest
+from isValidSudoku import Solution
+
+@pytest.fixture
+def inputs():
+    return [
+        (
+            [["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"]],
+            True
+        ),
+        (
+            [["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"]],
+            False
+        ),
+    ]
+def test_isValidSudoku(inputs):
+    for board, expected in inputs:
+        s = Solution()
+        assert s.isValidSudoku(board) == expected