Print Java Packages as Indented Tree

Problem Given fully-qualified Java names (e.g. java.util.vector, java.util.Date, org.json.JSONObject, java.util.regex.Pattern), print them as an indented tree grouped by package segment.

Input / Output

• Input: list of dotted names.
• Output: printed hierarchy, one segment per line, children indented under parents (e.g. java → util → {vector, Date, regex → Pattern}).

Constraints

• Up to 10^4 names; clarify sibling ordering (alphabetical vs insertion) and duplicate handling.

Example

• [java.util.vector, java.util.Date, org.json.JSONObject] → java / (indent) util / (indent×2) vector, Date; org / (indent) json / (indent×2) JSONObject.

Expected approach

• Build a trie of segments: nested Map<String, Node>, inserting each name split on '.'. DFS the trie printing segment names with depth-proportional indentation (preorder). O(total segments) build and print. Talking points: TreeMap for sorted output, marking terminal nodes if classes vs packages must be distinguished.