Longest Path With Different Adjacent Characters

Problem Overview

• Find the length of the longest path in a rooted tree where adjacent nodes have different characters.
• Inputs: 0-indexed parent array and string s of length n; output: the maximum path length.
• Constraints: n == parent.length == s.length, 1 <= n <= 1e5, valid tree with parent[0] = -1, lowercase letters.
• Domain: graph/tree path evaluation with character labels.
• From Microsoft interviews; a coding interview problem and common interview question on trees and strings.