What is Python's bisect module?
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Answer
The bisect module provides binary search functions for maintaining sorted lists in O(log n) time. bisect.bisect_left(lst, x) — returns the leftmost position where x can be inserted to keep the list sorted (elements equal to x go to the right of this position). bisect.bisect_right(lst, x) (same as bisect.bisect()) — returns the rightmost insertion point. bisect.insort_left(lst, x) — inserts x at the correct position (O(log n) search but O(n) insert due to list shifting). Example — grade classification: def grade(score): return "ABCDF"[bisect.bisect([60, 70, 80, 90], score)]. Finding the rank of a value in a sorted list: rank = bisect.bisect_left(sorted_list, value). Use bisect when you have a sorted list and frequently need to find positions or insert values while maintaining order. For frequent insertions, sortedcontainers.SortedList is more efficient.
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