How should I practice Generate Rand7 from Rand5?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Bloomberg LP phone screen problems in FastPrep.

Is Generate Rand7 from Rand5 associated with Bloomberg LP?

FastPrep tags this as a Bloomberg LP phone screen coding practice problem when the problem catalog has that company and stage context.

Generate Rand7 from Rand5

Bloomberg LP● MediumNEW GRADPHONE SCREEN

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Problem statement

draws contains successive results from a uniform rand5() function, each between 1 and 5. Consume draws in pairs to simulate one uniform rand7() result.

Return a value from 1 through 7 as soon as rejection sampling accepts a pair. Return -1 if the provided stream ends first.

Function

rand7FromRand5Draws(draws: int[]) → int

Examples

Example 1

draws = [5,5,2,3]return = 1

The first pair maps to 24 and is rejected. The second maps to 7, which becomes 1.

Constraints

0 <= draws.length <= 10^5.
Every draw is between 1 and 5.