Minimum Number of Vertices to Reach All Nodes

Author: BarthJr

minimum-number-of-vertices-to-reach-all-nodes.py

@@ -0,0 +1,24 @@
+# Given a directed acyclic graph, with n vertices numbered from 0 to n-1,
+# and an array edges where edges[i] = [from[i], to[i]] represents a directed edge from node from[i] to node to[i].
+#
+# Find the smallest set of vertices from which all nodes in the graph are reachable. It's guaranteed that a unique solution exists.
+#
+# Notice that you can return the vertices in any order.
+
+"""
+>>> Solution().findSmallestSetOfVertices(6, [[0,1],[0,2],[2,5],[3,4],[4,2]])
+[0, 3]
+>>> Solution().findSmallestSetOfVertices(5, [[0,1],[2,1],[3,1],[1,4],[2,4]])
+[0, 2, 3]
+"""
+from typing import List
+
+
+class Solution:
+    def findSmallestSetOfVertices(self, n: int, edges: List[List[int]]) -> List[int]:
+        nodes = [False for _ in range(n)]
+
+        for a, b in edges:
+            nodes[b] = True
+
+        return [i for i, node in enumerate(nodes) if not node]