feat: Add Solution.py

solution/1900-1999/1948.Delete Duplicate Folders in System/Solution.py

@@ -0,0 +1,52 @@
+from collections import defaultdict
+
+class TrieNode:
+    def __init__(self):
+        self.children = defaultdict(TrieNode)
+        self.id = None
+
+class Solution:
+    def deleteDuplicateFolder(self, paths):
+        # Step 1: Build a Trie (Tree) to represent the file system structure
+        root = TrieNode()
+
+        for path in paths:
+            node = root
+            for folder in path:
+                node = node.children[folder]
+
+        # Step 2: Assign unique IDs to the subtrees for easier comparison
+        subtree_map = defaultdict(list)
+        def get_id(node):
+            if not node.children:
+                return 0  # Empty subtree
+            subtree_tuple = tuple((name, get_id(child)) for name, child in sorted(node.children.items()))
+            subtree_id = hash(subtree_tuple)
+            subtree_map[subtree_id].append(node)
+            return subtree_id
+
+        get_id(root)
+
+        # Step 3: Mark duplicate subtrees by examining the subtree map
+        duplicates = set()
+        for nodes in subtree_map.values():
+            if len(nodes) > 1:  # If more than one node has the same subtree ID, mark as duplicate
+                for node in nodes:
+                    duplicates.add(node)
+
+        # Step 4: Reconstruct the remaining paths
+        ans = []
+
+        def collect_paths(node, path):
+            if node in duplicates:
+                return  # Skip this subtree because it's marked for deletion
+            if path:
+                ans.append(path[:])
+            for folder, child in sorted(node.children.items()):
+                path.append(folder)
+                collect_paths(child, path)
+                path.pop()
+
+        collect_paths(root, [])
+
+        return ans