Equalize Root-to-Leaf Path Sums in an N-ary Tree

After a warm-up (most frequent array element, ties broken toward the smaller number), the main problem gives an n-ary tree of integers where each operation increments one node's value by 1; return the minimum operations to make all root-to-leaf path sums equal. Both problems require self-written, executed test cases. Requirements You are given an n-ary (not binary) tree where every node holds an integer value. One operation increases the value of a single node by 1. Return the minimum number of operations needed to make every root-to-leaf path sum equal. You must write your own test cases and run them — the round grades self-verification, not just the algorithm. Examples 2 3 4 Answer: 1 — increase the 3 to 4. 1 2 3 2 2 3 3 Answer: 4 — increase each of the two leaf 2s to 4 (2 operations per leaf). Notes The interviewer accepted a post-order traversal: for each node, compute the maximum path sum among its child subtrees, charge (max - childSum) for each child that falls short, and propagate node.val + max upward. The second worked example's stated answer (4) matches applying increments only at the leaves, while the post-order greedy lifts the shared increment to the highest ancestor and yields a smaller count — clarify whether internal nodes may be incremented before committing to an approach. The screen opens with a short warm-up: given an integer array, return the most frequent element, breaking ties toward the smaller number — a single counting pass with a running best. The round also includes a brief behavioral opener (favorite project and its hardest technical challenge) before any coding. Preparation Drill post-order recursions that aggregate a value from children and charge a per-child correction cost, on both binary and n-ary trees. Practice building an n-ary Node class and a small test harness from a blank file, and run at least one test per problem before declaring done. Rehearse asking one clarifying question about operation constraints (which nodes may be modified) before writing code.