{ "data": { "question": { "questionId": "2717", "questionFrontendId": "2603", "boundTopicId": null, "title": "Collect Coins in a Tree", "titleSlug": "collect-coins-in-a-tree", "content": "

There exists an undirected and unrooted tree with n nodes indexed from 0 to n - 1. You are given an integer n and a 2D integer array edges of length n - 1, where edges[i] = [ai, bi] indicates that there is an edge between nodes ai and bi in the tree. You are also given an array coins of size n where coins[i] can be either 0 or 1, where 1 indicates the presence of a coin in the vertex i.

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Initially, you choose to start at any vertex in the tree. Then, you can perform the following operations any number of times: 

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Find the minimum number of edges you need to go through to collect all the coins and go back to the initial vertex.

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Note that if you pass an edge several times, you need to count it into the answer several times.

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Example 1:

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\nInput: coins = [1,0,0,0,0,1], edges = [[0,1],[1,2],[2,3],[3,4],[4,5]]\nOutput: 2\nExplanation: Start at vertex 2, collect the coin at vertex 0, move to vertex 3, collect the coin at vertex 5 then move back to vertex 2.\n
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Example 2:

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\nInput: coins = [0,0,0,1,1,0,0,1], edges = [[0,1],[0,2],[1,3],[1,4],[2,5],[5,6],[5,7]]\nOutput: 2\nExplanation: Start at vertex 0, collect the coins at vertices 4 and 3, move to vertex 2,  collect the coin at vertex 7, then move back to vertex 0.\n
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Constraints:

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(listof (listof exact-integer?)) exact-integer?)\n\n )", "__typename": "CodeSnippetNode" }, { "lang": "Erlang", "langSlug": "erlang", "code": "-spec collect_the_coins(Coins :: [integer()], Edges :: [[integer()]]) -> integer().\ncollect_the_coins(Coins, Edges) ->\n .", "__typename": "CodeSnippetNode" }, { "lang": "Elixir", "langSlug": "elixir", "code": "defmodule Solution do\n @spec collect_the_coins(coins :: [integer], edges :: [[integer]]) :: integer\n def collect_the_coins(coins, edges) do\n\n end\nend", "__typename": "CodeSnippetNode" }, { "lang": "Dart", "langSlug": "dart", "code": "class Solution {\n int collectTheCoins(List coins, List> edges) {\n\n }\n}", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"135\", \"totalSubmission\": \"813\", \"totalAcceptedRaw\": 135, \"totalSubmissionRaw\": 813, \"acRate\": \"16.6%\"}", "hints": [ "All leaves that do not have a coin are redundant and can be deleted from the tree.", "Remove the leaves that do not have coins on them, so that the resulting tree will have a coin on every leaf.", "In the remaining tree, remove each leaf node and its parent from the tree. The remaining nodes in the tree are the ones that must be visited. Hence, the answer is equal to (# remaining nodes -1) * 2" ], "solution": null, "status": null, "sampleTestCase": "[1,0,0,0,0,1]\n[[0,1],[1,2],[2,3],[3,4],[4,5]]", "metaData": "{\n \"name\": \"collectTheCoins\",\n \"params\": [\n {\n \"name\": \"coins\",\n \"type\": \"integer[]\"\n },\n {\n \"type\": \"integer[][]\",\n \"name\": \"edges\"\n }\n ],\n \"return\": {\n \"type\": \"integer\"\n }\n}", "judgerAvailable": true, "judgeType": "large", "mysqlSchemas": [], "enableRunCode": true, "enableTestMode": false, "enableDebugger": true, "envInfo": "{\"cpp\": [\"C++\", \"

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Most standard library headers are already included automatically for your convenience.

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C# 10 with .NET 6 runtime

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Ruby 3.1

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Python 3.10.

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