What is the time complexity of rabin-karp?

Average case O(n + m). Worst case O(n·m). Space complexity is O(1). The worst case needs collisions at every position, which a large modulus makes unlikely.

Rabin-Karp

medium

Rolling the window's hash costs O(1) instead of O(m). Equal hashes are a hint, not a proof - watch a deliberate collision get caught by the verification step.

Average O(n + m)Worst O(n·m)Space O(1)

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Where to go next

KMP pattern matching

hard

The text pointer never moves backwards.

Naive pattern search

easy

Slide one place right and start over.

Hash table with chaining

medium

Collisions share a bucket, and load factor is everything.