Matrix - medium - valid sudoku implementation

Author: rajithst

matrix/medium/valid_sudoku.py

@@ -0,0 +1,31 @@
+from typing import List
+
+
+class Solution:
+    def isValidSudoku(self, board: List[List[str]]) -> bool:
+        n = 9
+        rows = [set() for _ in range(n)]
+        cols = [set() for _ in range(n)]
+        boxs = [set() for _ in range(n)]
+
+        for x in range(n):
+            for y in range(n):
+                val = board[x][y]
+                if val == ".":
+                    continue
+                # check if already in row values
+                if val in rows[x]:
+                    return False
+                rows[x].add(val)
+                # check if already in cols values
+                if val in cols[y]:
+                    return False
+                cols[y].add(val)
+
+                # check its in the box
+                box_id = (x // 3) * 3 + y // 3
+                if val in boxs[box_id]:
+                    return False
+                boxs[box_id].add(val)
+        return True
+