Solution: Random Pick with Weight
Explore how to implement a weighted random selection of array indices based on their weights using running sums and modified binary search. Understand how to optimize the naive linear search approach to achieve logarithmic time complexity, ensuring efficient selection proportional to weights.
Statement
You’re given an array of positive integers, weights, where weights[i] is the weight of the index.
Write a function, Pick Index(), which performs weighted random selection to return an index from the weights array. The larger the value of weights[i], the heavier the weight is, and the higher the chances of its index being picked.
Suppose that the array consists of the weights . In this case, the probabilities of picking the indexes will be as follows:
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Index 0:
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Index 1: ...