feat: valid-sudoku

Author: junbinding

dfs.valid-sudoku.py

@@ -0,0 +1,66 @@
+from typing import List
+
+
+class Solution:
+    """
+    36. 有效的数独
+    https://leetcode-cn.com/problems/valid-sudoku
+    判断一个 9x9 的数独是否有效。只需要根据以下规则，验证已经填入的数字是否有效即可。
+    1. 数字 1-9 在每一行只能出现一次。
+    2. 数字 1-9 在每一列只能出现一次。
+    3. 数字 1-9 在每一个以粗实线分隔的 3x3 宫内只能出现一次。
+    """
+    def isValidSudoku(self, board: List[List[str]]) -> bool:
+        # 判断行是否满足
+        # 判断列是否满足
+        col_sets = [set() for _ in range(9)]
+        row_sets = [set() for _ in range(9)]
+        block_sets = [set() for _ in range(9)]
+
+        for i in range(9):
+            for j in range(9):
+                if board[i][j] == '.':
+                    continue
+
+                if board[i][j] in row_sets[i]:
+                    return False
+
+                if board[i][j] in col_sets[j]:
+                    return False
+
+                if board[i][j] in block_sets[(i // 3) * 3 + j // 3]:
+                    return False
+
+                row_sets[i].add(board[i][j])
+                col_sets[j].add(board[i][j])
+                block_sets[(i // 3) * 3 + j // 3].add(board[i][j])
+
+        return True
+
+
+so = Solution()
+# True
+print(so.isValidSudoku([
+  ["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"]
+]))
+
+# False
+print(so.isValidSudoku([
+  ["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"]
+]))