Solution: Random Pick with Weight
Explore the solution for weighted random index selection by transforming weights into running sums and using modified binary search to pick indices proportional to their weight. Learn how this approach optimizes both time complexity and implementation efficiency.
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: ...