Date: 2026-06-06
Time: 16:21
This file solves LeetCode 2446: Determine if Two Events Have Conflict. It owns the single responsibility of checking whether two time intervals on the same day overlap.
haseventconflict(event1, event2) -> boolTakes two events, each represented as a [startTime, endTime] pair in "HH:MM" string format, and returns whether they overlap.
The implementation is a single expression:
return event1[0] <= event2[1] and event2[0] <= event1[1]
This is the standard interval overlap test: two intervals [a, b] and [c, d] overlap if and only if a <= d and c <= b. It's the negation of the non-overlap condition (a > d or c > b).
Lexicographic string comparison as time comparison. The code compares "HH:MM" strings directly with <= instead of parsing them into integers or datetime objects. This works because "HH:MM" is a fixed-width, zero-padded format where lexicographic order equals chronological order (e.g., "09:30" < "10:00" < "23:59"). This is a common idiom in LeetCode solutions for time-formatted strings.
Closed-interval overlap formula. Both endpoints are inclusive — events sharing an exact boundary time (e.g., one ends at "10:00" and the other starts at "10:00") are considered conflicting. The <= (not <) enforces this.
List from typing — used only for the type annotation. No runtime dependency.determine-if-two-events-have-conflict/test_solution.py directly. The massive "Imported By" list in the prompt is an artifact of the test harness structure — those other test files import from their own solutions, not from this one.1. Caller passes two lists of two "HH:MM" strings each.
2. The function performs two string comparisons and returns their conjunction.
3. No mutation, no side effects, no iteration.
Constant time and space: O(1).
"HH:MM" zero-padded 24-hour format for the lexicographic comparison to be valid. "9:30" instead of "09:30" would break correctness.[start, end] with start <= end.None. The function trusts its inputs per LeetCode conventions — no validation of format, length, or ordering. An IndexError would propagate naturally if a list had fewer than two elements.
determine-if-two-events-have-conflict/test_solution.py — See what edge cases the tests cover (boundary overlap, identical events, no overlap)determine-if-two-events-have-conflict/plan.md — The approach reasoning and any alternatives considered before implementationmeeting-rooms/solution.py — A related interval-overlap problem that extends to N intervals and requires sortinginterval-overlap-patterns — The closed vs. open interval distinction and how it affects the comparison operators usedcount-days-spent-together/solution.py — Another date/time overlap problem that likely uses a similar interval intersection techniquelexicographic-hhmm-is-chronological — Comparing "HH:MM" strings with <= produces correct chronological ordering because the format is fixed-width and zero-paddedoverlap-test-is-inclusive — Two events that share only a single boundary moment (e.g., ["10:00","10:00"] and ["10:00","11:00"]) are reported as conflictingno-input-validation — The function performs no validation on input format, list length, or start-before-end ordering; it trusts the callerconstant-time-complexity — The function executes exactly two string comparisons regardless of input, making it O(1) time and space