{ "data": { "question": { "questionId": "1661", "questionFrontendId": "1557", "boundTopicId": null, "title": "Minimum Number of Vertices to Reach All Nodes", "titleSlug": "minimum-number-of-vertices-to-reach-all-nodes", "content": "

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.

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Find the smallest set of vertices from which all nodes in the graph are reachable. It's guaranteed that a unique solution exists.

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Notice that you can return the vertices in any order.

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Example 1:

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\r\nInput: n = 6, edges = [[0,1],[0,2],[2,5],[3,4],[4,2]]\r\nOutput: [0,3]\r\nExplanation: 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].
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Example 2:

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\r\nInput: n = 5, edges = [[0,1],[2,1],[3,1],[1,4],[2,4]]\r\nOutput: [0,2,3]\r\nExplanation: 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.\r\n
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Constraints:

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