Package g1501_1600.s1557_minimum_number_of_vertices_to_reach_all_nodes

Class Solution

java.lang.Object

g1501_1600.s1557_minimum_number_of_vertices_to_reach_all_nodes.Solution

public class Solution
extends Object

1557 - Minimum Number of Vertices to Reach All Nodes\. Medium Given a** directed acyclic graph** , with `n` vertices numbered from `0` to `n-1`, and an array `edges` where edges[i] = [fromi, toi] represents a directed edge from node fromi to node toi. 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. **Example 1:**  **Input:** n = 6, edges = \[\[0,1],[0,2],[2,5],[3,4],[4,2]] **Output:** [0,3] **Explanation:** It's not possible to reach all the nodes from a single vertex. From 0 we can reach [0,1,2,5]. From 3 we can reach [3,4,2,5]. So we output [0,3]. **Example 2:**  **Input:** n = 5, edges = \[\[0,1],[2,1],[3,1],[1,4],[2,4]] **Output:** [0,2,3] **Explanation:** Notice that vertices 0, 3 and 2 are not reachable from any other node, so we must include them. Also any of these vertices can reach nodes 1 and 4. **Constraints:** * `2 <= n <= 10^5` * `1 <= edges.length <= min(10^5, n * (n - 1) / 2)` * `edges[i].length == 2` * 0 <= fromi, toi < n * All pairs (fromi, toi) are distinct.

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
List<Integer>	findSmallestSetOfVertices(int n, List<List<Integer>> edges)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Solution

public Solution()

Method Details

findSmallestSetOfVertices

public List<Integer> findSmallestSetOfVertices(int n,
 List<List<Integer>> edges)