Solution: Random Pick with Weight
Explore how to solve the weighted random index selection problem by creating a running sums array and using modified binary search to pick an index proportional to its weight. Understand the algorithm’s steps, time complexity, and space considerations for an optimized solution.
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:
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Index 2: ...