Practice Random Pick with Blacklist
Master the Random Pick with Blacklist LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Random Pick with Blacklist
Solution(n,blacklist) defines allowed integers from zero through n-1 excluding the distinct blacklist entries. pick() must select every allowed integer with equal probability while minimizing random-function calls. Practice approach: Let m be the number of allowed values. Remap blacklisted values below m to distinct allowed values in [m,n). Sample once from [0,m) and apply that mapping if present. This creates a bijection to allowed values without repeated rejection when most small values are blocked. Test an empty blacklist and all but one value blocked.
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Understanding the Random Pick with Blacklist Problem
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Problem Statement
Solution(n,blacklist) defines allowed integers from zero through n-1 excluding the distinct blacklist entries. pick() must select every allowed integer with equal probability while minimizing random-function calls. Practice approach: Let m be the number of allowed values. Remap blacklisted values below m to distinct allowed values in [m,n). Sample once from [0,m) and apply that mapping if present. This creates a bijection to allowed values without repeated rejection when most small values are blocked. Test an empty blacklist and all but one value blocked.
Source: Random Pick with Blacklist on LeetCode. Use the original task for its coding environment and submissions.
Random Pick with Blacklist
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Examples
# Example 1
["Solution","pick","pick"] [[5,[0,2,4]],[],[]]
[null,3,1]
Only 1 and 3 are allowed, each with probability one half. The displayed sequence is one possible outcome.
Constraints
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