[LeetCode] Binary Tree diameter 543. Diameter of the binary tree (Easy) (JAVA)
Topic Address: https://leetcode.com/problems/diameter-of-binary-tree/
Subject description:
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 longest path 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.
Subject to the effect
Given a binary tree, you need to calculate the length of its diameter. A binary tree is the maximum length of the diameter of any two nodes in the path lengths. This path may pass through the root.
Problem-solving approach
The longest path left subtree path lengths of any two nodes == any node
and traversal, then calculated the all nodes around node maximum
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
int max = 0;
public int diameterOfBinaryTree(TreeNode root) {
height(root);
return max;
}
public int height(TreeNode root) {
if (root == null) return 0;
int left = height(root.left);
int right = height(root.right);
if ((left + right) > max) max = left + right;
return Math.max(left, right) + 1;
}
}
When execution: 0 ms, defeated 100.00% of all users to submit in Java
memory consumption: 39.3 MB, beat the 5.08% of all users to submit in Java
