| | | 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.PathSum; |
| | | 15 | | |
| | | 16 | | /// <inheritdoc /> |
| | | 17 | | public class PathSumDepthFirstSearch : IPathSum |
| | | 18 | | { |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n) |
| | | 21 | | /// Space complexity O(log n) for a balanced tree and O(n) for a skewed tree. |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="root"></param> |
| | | 24 | | /// <param name="targetSum"></param> |
| | | 25 | | /// <returns></returns> |
| | | 26 | | public bool HasPathSum(TreeNode? root, int targetSum) |
| | 7 | 27 | | { |
| | 7 | 28 | | return root != null && HasPathSum(root, targetSum, root.val); |
| | 7 | 29 | | } |
| | | 30 | | |
| | | 31 | | private static bool HasPathSum(TreeNode root, int targetSum, int currentSum) |
| | 20 | 32 | | { |
| | 20 | 33 | | if (root.left == null && root.right == null && currentSum == targetSum) |
| | 3 | 34 | | { |
| | 3 | 35 | | return true; |
| | | 36 | | } |
| | | 37 | | |
| | 17 | 38 | | if (root.left != null && HasPathSum(root.left, targetSum, currentSum + root.left.val)) |
| | 5 | 39 | | { |
| | 5 | 40 | | return true; |
| | | 41 | | } |
| | | 42 | | |
| | 12 | 43 | | return root.right != null && HasPathSum(root.right, targetSum, currentSum + root.right.val); |
| | 20 | 44 | | } |
| | | 45 | | } |