Jul 19

Author: siddydutta

2025-07-July-LeetCoding-Challenge/README.md

@@ -22,7 +22,7 @@
 | July 16 | [3201. Find the Maximum Length of Valid Subsequence I](https://leetcode.com/problems/find-the-maximum-length-of-valid-subsequence-i/) | Medium | Solved |
 | July 17 | [3202. Find the Maximum Length of Valid Subsequence II](https://leetcode.com/problems/find-the-maximum-length-of-valid-subsequence-ii/) | Medium | Unsolved |
 | July 18 | [2163. Minimum Difference in Sums After Removal of Elements](https://leetcode.com/problems/minimum-difference-in-sums-after-removal-of-elements/) | Hard | Unsolved |
-| July 19 | []() |  |  |
+| July 19 | [1233. Remove Sub-Folders from the Filesystem](https://leetcode.com/problems/remove-sub-folders-from-the-filesystem/) | Medium | Solved |
 | July 20 | []() |  |  |
 | July 21 | []() |  |  |
 | July 22 | []() |  |  |
@@ -41,5 +41,5 @@
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 5 | 5 | 0 |
-| Medium | 7 | 6 | 1 |
+| Medium | 8 | 7 | 1 |
 | Hard   | 6 | 1 | 5 |

2025-07-July-LeetCoding-Challenge/Remove Sub-Folders from the Filesystem.py

@@ -0,0 +1,50 @@
+from typing import Generator
+
+
+class TrieNode:
+    def __init__(self):
+        self.children = {}
+        self.is_end = False
+
+
+class Trie:
+    def __init__(self):
+        self.root = TrieNode()
+
+    def insert(self, path: str) -> None:
+        node = self.root
+        for folder in path.split('/')[1:]:
+            node = node.children.setdefault(folder, TrieNode())
+            if node.is_end:
+                return
+        node.is_end = True
+        node.children.clear()
+
+    def collect(self, node: TrieNode, path: str = '') -> Generator[str, None, None]:
+        if node.is_end:
+            yield path
+        for folder, child in node.children.items():
+            yield from self.collect(child, f'{path}/{folder}')
+
+
+class Solution:
+    def removeSubfolders(self, folder: list[str]) -> list[str]:
+        trie = Trie()
+        for path in folder:
+            trie.insert(path)
+        return list(trie.collect(trie.root))
+
+
+def main():
+    folders = ['/a', '/a/b', '/c/d', '/c/d/e', '/c/f']
+    assert Solution().removeSubfolders(folders) == ['/a', '/c/d', '/c/f']
+
+    folders = ['/a', '/a/b/c', '/a/b/d']
+    assert Solution().removeSubfolders(folders) == ['/a']
+
+    folders = ['/a/b/c', '/a/b/d', '/a/b/c/e']
+    assert Solution().removeSubfolders(folders) == ['/a/b/c', '/a/b/d']
+
+
+if __name__ == '__main__':
+    main()