Jan 29

Author: siddydutta

2025-01-January-LeetCoding-Challenge/README.md

@@ -31,7 +31,7 @@
 | January 26 | [2127. Maximum Employees to Be Invited to a Meeting](https://leetcode.com/problems/maximum-employees-to-be-invited-to-a-meeting/) | Hard | Unsolved |
 | January 27 | [1462. Course Schedule IV](https://leetcode.com/problems/course-schedule-iv/) | Medium | Solved |
 | January 28 | [2658. Maximum Number of Fish in a Grid](https://leetcode.com/problems/maximum-number-of-fish-in-a-grid/) | Medium | Solved |
-| January 29 | []() |  |  |
+| January 29 | [684. Redundant Connection](https://leetcode.com/problems/redundant-connection/) | Medium | Solved |
 | January 30 | []() |  |  |
 | January 31 | []() |  |  |
 
@@ -40,5 +40,5 @@
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 4 | 4 | 0 |
-| Medium | 20 | 17 | 3 |
+| Medium | 21 | 18 | 3 |
 | Hard   | 3 | 0 | 3 |

2025-01-January-LeetCoding-Challenge/Redundant Connection.py

@@ -0,0 +1,37 @@
+from typing import List
+
+
+class UnionFind:
+    def __init__(self, n: int):
+        self.parent = list(range(n+1))
+
+    def find(self, x: int) -> int:
+        if x != self.parent[x]:
+            self.parent[x] = self.find(self.parent[x])
+        return self.parent[x]
+
+    def union(self, x: int, y: int) -> None:
+        self.parent[self.find(x)] = self.find(y)
+
+
+class Solution:
+    def findRedundantConnection(self, edges: List[List[int]]) -> List[int]:
+        uf = UnionFind(len(edges))
+        for u, v in edges:
+            if uf.find(u) == uf.find(v):
+                return [u, v]
+            else:
+                uf.union(u, v)
+        return None
+
+
+def main():
+    edges = [[1, 2], [1, 3], [2, 3]]
+    assert Solution().findRedundantConnection(edges) == [2, 3]
+
+    edges = [[1, 2], [2, 3], [3, 4], [1, 4], [1, 5]]
+    assert Solution().findRedundantConnection(edges) == [1, 4]
+
+
+if __name__ == '__main__':
+    main()