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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
function diameterOfBinaryTree(root: TreeNode | null): number {
let ans = 0
function dfs(node: TreeNode | null): number {
if (node === null) {
return 0
}
let left = dfs(node.left)
let right = dfs(node.right)
ans = Math.max(ans, left + right)
return Math.max(left, right) + 1
}
dfs(root)
return ans
}
export { diameterOfBinaryTree }