| | | 1 | | // -------------------------------------------------------------------------------- |
| | | 2 | | // Copyright (C) 2025 Eugene Eremeev (also known as Yevhenii Yeriemeieiv). |
| | | 3 | | // All Rights Reserved. |
| | | 4 | | // -------------------------------------------------------------------------------- |
| | | 5 | | // This software is the confidential and proprietary information of Eugene Eremeev |
| | | 6 | | // (also known as Yevhenii Yeriemeieiv) ("Confidential Information"). You shall not |
| | | 7 | | // disclose such Confidential Information and shall use it only in accordance with |
| | | 8 | | // the terms of the license agreement you entered into with Eugene Eremeev (also |
| | | 9 | | // known as Yevhenii Yeriemeieiv). |
| | | 10 | | // -------------------------------------------------------------------------------- |
| | | 11 | | |
| | | 12 | | namespace LeetCode.Algorithms.FindMinimumDiameterAfterMergingTwoTrees; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public class FindMinimumDiameterAfterMergingTwoTreesDepthFirstSearch : IFindMinimumDiameterAfterMergingTwoTrees |
| | | 16 | | { |
| | | 17 | | /// <summary> |
| | | 18 | | /// Time complexity - O(n + m) |
| | | 19 | | /// Space complexity - O(n + m) |
| | | 20 | | /// </summary> |
| | | 21 | | /// <param name="edges1"></param> |
| | | 22 | | /// <param name="edges2"></param> |
| | | 23 | | /// <returns></returns> |
| | | 24 | | public int MinimumDiameterAfterMerge(int[][] edges1, int[][] edges2) |
| | 2 | 25 | | { |
| | 2 | 26 | | var adjList1 = BuildAdjList(edges1.Length + 1, edges1); |
| | 2 | 27 | | var adjList2 = BuildAdjList(edges2.Length + 1, edges2); |
| | | 28 | | |
| | 2 | 29 | | var diameter1 = FindDiameter(adjList1, 0, -1).Item1; |
| | 2 | 30 | | var diameter2 = FindDiameter(adjList2, 0, -1).Item1; |
| | | 31 | | |
| | 2 | 32 | | var combinedDiameter = (int)Math.Ceiling(diameter1 / 2.0) + (int)Math.Ceiling(diameter2 / 2.0) + 1; |
| | | 33 | | |
| | 2 | 34 | | return Math.Max(Math.Max(diameter1, diameter2), combinedDiameter); |
| | 2 | 35 | | } |
| | | 36 | | |
| | | 37 | | private static List<List<int>> BuildAdjList(int size, int[][] edges) |
| | 4 | 38 | | { |
| | 4 | 39 | | var adjList = new List<List<int>>(size); |
| | | 40 | | |
| | 52 | 41 | | for (var i = 0; i < size; i++) |
| | 22 | 42 | | { |
| | 22 | 43 | | adjList.Add([]); |
| | 22 | 44 | | } |
| | | 45 | | |
| | 48 | 46 | | foreach (var edge in edges) |
| | 18 | 47 | | { |
| | 18 | 48 | | adjList[edge[0]].Add(edge[1]); |
| | 18 | 49 | | adjList[edge[1]].Add(edge[0]); |
| | 18 | 50 | | } |
| | | 51 | | |
| | 4 | 52 | | return adjList; |
| | 4 | 53 | | } |
| | | 54 | | |
| | | 55 | | private static (int Diameter, int Depth) FindDiameter(List<List<int>> adjList, int node, int parent) |
| | 22 | 56 | | { |
| | 22 | 57 | | var maxDepth1 = 0; |
| | 22 | 58 | | var maxDepth2 = 0; |
| | 22 | 59 | | var diameter = 0; |
| | | 60 | | |
| | 138 | 61 | | foreach (var neighbor in adjList[node].Where(neighbor => neighbor != parent)) |
| | 18 | 62 | | { |
| | 18 | 63 | | var (childDiameter, childDepth) = FindDiameter(adjList, neighbor, node); |
| | | 64 | | |
| | 18 | 65 | | var depth = childDepth + 1; |
| | | 66 | | |
| | 18 | 67 | | diameter = Math.Max(diameter, childDiameter); |
| | | 68 | | |
| | 18 | 69 | | if (depth > maxDepth1) |
| | 10 | 70 | | { |
| | 10 | 71 | | maxDepth2 = maxDepth1; |
| | 10 | 72 | | maxDepth1 = depth; |
| | 10 | 73 | | } |
| | 8 | 74 | | else if (depth > maxDepth2) |
| | 5 | 75 | | { |
| | 5 | 76 | | maxDepth2 = depth; |
| | 5 | 77 | | } |
| | 18 | 78 | | } |
| | | 79 | | |
| | 22 | 80 | | diameter = Math.Max(diameter, maxDepth1 + maxDepth2); |
| | | 81 | | |
| | 22 | 82 | | return (diameter, maxDepth1); |
| | 22 | 83 | | } |
| | | 84 | | } |