Reverse a List Up To K | Dataford Interview Questions

A Nasdaq Market Surveillance component receives events in a list and needs to reverse only the first k events while preserving the order of all remaining events. Implement this transformation in place and return the modified list.

Formal Specification

Given a list events of values and a non-negative integer k, reverse the prefix containing the first k elements. If k is greater than the list length, reverse the entire list. The function must modify the input list directly and return it.

The input consists of events, a list of integers, and k, an integer. The output is the same list object after the requested prefix has been reversed.

Constraints

0 <= len(events) <= 10^5
0 <= k <= 10^9
events contains integers
Reverse at most min(k, len(events)) elements
Use O(1) auxiliary space

Function Signature

def reverse_prefix(events, k):

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