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543. Diameter of Binary Tree
Easy
Given the root of a binary tree, return the length of the diameter of the tree.
The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root.
The length of a path between two nodes is represented by the number of edges between them.
Example 1:
Input: root = [1,2,3,4,5]
Output: 3
Explanation: 3 is the length of the path [4,2,1,3] or [5,2,1,3].
Example 2:
Input: root = [1,2]
Output: 1
Constraints:
- The number of nodes in the tree is in the range
[1, 104]. -100 <= Node.val <= 100
Solution
using LeetCodeNet.Com_github_leetcode;
/**
* Definition for a binary tree node.
* public class TreeNode {
* public int val;
* public TreeNode left;
* public TreeNode right;
* public TreeNode(int val=0, TreeNode left=null, TreeNode right=null) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
public class Solution {
private int diameter;
public int DiameterOfBinaryTree(TreeNode root) {
diameter = 0;
DiameterOfBinaryTreeUtil(root);
return diameter;
}
private int DiameterOfBinaryTreeUtil(TreeNode root) {
if (root == null) {
return 0;
}
int leftLength = root.left != null ? 1 + DiameterOfBinaryTreeUtil(root.left) : 0;
int rightLength = root.right != null ? 1 + DiameterOfBinaryTreeUtil(root.right) : 0;
diameter = Math.Max(diameter, leftLength + rightLength);
return Math.Max(leftLength, rightLength);
}
}