Code Room
CodingMediumcod-g429
Subject Sweep lineLevel Mid–Senior~20 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given a list of [start, end) intervals on the number line, return the total length covered by their union (overlapping regions counted once). For example [[1,4),[2,6),[8,10)] covers length 7. There are up to 10^5 intervals and coordinates fit in 64-bit ints.

Implement
union_length(intervals: list[list[int]]) → int
Examples
in[[[1,4],[2,6],[8,10]]]out7
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.