Solution: Random Pick with Weight
Explore how to perform weighted random selection of an index from an array by transforming weights into running sums and applying modified binary search. Understand the step-by-step method to generate biased selections in efficient time, enhancing your ability to solve similar coding interview problems.
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: ...