| | | 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 | | using LeetCode.Core.Models; |
| | | 13 | | |
| | | 14 | | namespace LeetCode.Algorithms.DeleteNodesAndReturnForest; |
| | | 15 | | |
| | | 16 | | /// <inheritdoc /> |
| | | 17 | | public class DeleteNodesAndReturnForestDepthFirstSearchStack : IDeleteNodesAndReturnForest |
| | | 18 | | { |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n + d) |
| | | 21 | | /// Space complexity - O(n + d) |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="root"></param> |
| | | 24 | | /// <param name="to_delete"></param> |
| | | 25 | | /// <returns></returns> |
| | | 26 | | public IList<TreeNode> DelNodes(TreeNode? root, int[] to_delete) |
| | 8 | 27 | | { |
| | 8 | 28 | | if (root == null) |
| | 1 | 29 | | { |
| | 1 | 30 | | return new List<TreeNode>(); |
| | | 31 | | } |
| | | 32 | | |
| | 7 | 33 | | var result = new List<TreeNode>(); |
| | | 34 | | |
| | 7 | 35 | | var toDeleteHashSet = new HashSet<int>(to_delete); |
| | 7 | 36 | | var stack = new Stack<TreeNode>(); |
| | | 37 | | |
| | 7 | 38 | | var dummyNode = new TreeNode { left = root }; |
| | | 39 | | |
| | 7 | 40 | | stack.Push(dummyNode); |
| | | 41 | | |
| | 65 | 42 | | while (stack.Count > 0) |
| | 58 | 43 | | { |
| | 58 | 44 | | var node = stack.Pop(); |
| | | 45 | | |
| | 58 | 46 | | if (node.left != null) |
| | 28 | 47 | | { |
| | 28 | 48 | | stack.Push(node.left); |
| | | 49 | | |
| | 28 | 50 | | if (toDeleteHashSet.Contains(node.left.val)) |
| | 11 | 51 | | { |
| | 11 | 52 | | if (node.left.left != null && !toDeleteHashSet.Contains(node.left.left.val)) |
| | 3 | 53 | | { |
| | 3 | 54 | | result.Add(node.left.left); |
| | 3 | 55 | | } |
| | | 56 | | |
| | 11 | 57 | | if (node.left.right != null && !toDeleteHashSet.Contains(node.left.right.val)) |
| | 2 | 58 | | { |
| | 2 | 59 | | result.Add(node.left.right); |
| | 2 | 60 | | } |
| | | 61 | | |
| | 11 | 62 | | node.left = null; |
| | 11 | 63 | | } |
| | 28 | 64 | | } |
| | | 65 | | |
| | 58 | 66 | | if (node.right != null) |
| | 23 | 67 | | { |
| | 23 | 68 | | stack.Push(node.right); |
| | | 69 | | |
| | 23 | 70 | | if (toDeleteHashSet.Contains(node.right.val)) |
| | 12 | 71 | | { |
| | 12 | 72 | | if (node.right.left != null && !toDeleteHashSet.Contains(node.right.left.val)) |
| | 3 | 73 | | { |
| | 3 | 74 | | result.Add(node.right.left); |
| | 3 | 75 | | } |
| | | 76 | | |
| | 12 | 77 | | if (node.right.right != null && !toDeleteHashSet.Contains(node.right.right.val)) |
| | 3 | 78 | | { |
| | 3 | 79 | | result.Add(node.right.right); |
| | 3 | 80 | | } |
| | | 81 | | |
| | 12 | 82 | | node.right = null; |
| | 12 | 83 | | } |
| | 23 | 84 | | } |
| | 58 | 85 | | } |
| | | 86 | | |
| | 7 | 87 | | if (dummyNode.left != null) |
| | 4 | 88 | | { |
| | 4 | 89 | | result.Add(dummyNode.left); |
| | 4 | 90 | | } |
| | | 91 | | |
| | 7 | 92 | | return result; |
| | 8 | 93 | | } |
| | | 94 | | } |