Q55: Diameter of Binary Tree. - DSA Patterns (Multi-Lang)

In Simple Words: At each node, the longest path passing through it is leftDepth + rightDepth. Update global max diameter while bottom-up recursion returns 1 + max(left, right).

Time: $O(N)$ | Space: $O(H)$

Multi-Language SolutionsPython 3 • JavaScript • TypeScript • Java • C++

Switch tabs or choose All

def diameterOfBinaryTree(root: TreeNode | None) -> int:
    diameter = 0
    def dfs(node):
        nonlocal diameter
        if not node: return 0
        left = dfs(node.left)
        right = dfs(node.right)
        diameter = max(diameter, left + right)
        return 1 + max(left, right)
    dfs(root)
    return diameter