Maximum Movies You Can Watch

Problem Given a list of movies each with a start and an end time, find the maximum number of movies you can watch such that no two of them overlap.

Input / Output

• Input: a list of n intervals (start_i, end_i).
• Output: an integer — the largest possible count of mutually non-overlapping movies (extension: the actual schedule chosen).

Constraints

• 1 <= n <= 10^5; times may overlap arbitrarily.
• Clarify whether a movie ending exactly when another starts counts as a conflict — usually it does not, which makes the check start >= lastEnd rather than >.
• Movie length and desirability are irrelevant here; only the count is being maximised.

Example

• [(1,3),(2,4),(3,5),(6,8)] → 3, e.g. (1,3), (3,5), (6,8).
• [(1,10),(2,3),(4,5),(6,7)] → 3. Sorting by start time picks the long (1,10) first and yields only 1 — the counterexample that rules out the obvious alternative sort key.