solve: graph valid tree

Author: sounmind

graph-valid-tree/evan.py

@@ -0,0 +1,40 @@
+from typing import List
+
+
+class Solution:
+    def validTree(self, n: int, edges: List[List[int]]) -> bool:
+        # If the number of edges is not equal to n-1, it can't be a tree
+        if len(edges) != n - 1:
+            return False
+
+        # Initialize node_list array where each node is its own parent
+        node_list = list(range(n))
+
+        # Find root function with path compression
+        def find_root(node):
+            if node_list[node] != node:
+                node_list[node] = find_root(node_list[node])
+
+            return node_list[node]
+
+        def union_and_check_cycle(node1, node2):
+            root1 = find_root(node1)
+            root2 = find_root(node2)
+
+            if root1 != root2:
+                node_list[root2] = root1
+                return True
+            else:
+                return False
+
+        for node1, node2 in edges:
+            if not union_and_check_cycle(node1, node2):
+                return False
+
+        return True
+
+
+# Example usage:
+solution = Solution()
+print(solution.validTree(5, [[0, 1], [0, 2], [0, 3], [1, 4]]))  # Output: True
+print(solution.validTree(5, [[0, 1], [1, 2], [2, 3], [1, 3], [1, 4]]))  # Output: False