Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longestpath between any two nodes in a tree. This path may or may not pass through the root.
Example:
Given a binary tree
1
/ 2 3
/ \
4 5
Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].
Note: The length of path between two nodes is represented by the number of edges between them.
1 /** 2 * Definition for a binary tree node. 3 * public class TreeNode { 4 * public int val; 5 * public TreeNode left; 6 * public TreeNode right; 7 * public TreeNode(int x) { val = x; } 8 * } 9 */ 10 public class Solution { 11 public int DiameterOfBinaryTree(TreeNode root) { 12 int curMax = 0; 13 14 DFS(root, ref curMax); 15 16 return curMax > 0 ? curMax - 1 : 0; 17 } 18 19 private int DFS(TreeNode node, ref int curMax) 20 { 21 if (node == null) return 0; 22 23 int left = DFS(node.left, ref curMax); 24 int right = DFS(node.right, ref curMax); 25 26 curMax = Math.Max(curMax, left + right + 1); 27 return Math.Max(left + 1, right + 1); 28 } 29 }
