Find the number of contiguous subarrays in a given array whose least common multiple (LCM) is equal to a target value K.

Design a data structure that supports insertion, deletion, and random element retrieval, all in constant time on average. You'll need to handle edge cases carefully to achieve O(1) complexity.

Two players alternate removing colored pieces from a line. Determine who wins if both neighbors of a piece are the same color, and players try to maximize their moves.