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Suppose you want to generate all permutations of n elements where elements can be repeated unlimited times. Which approach best handles this variant?

hard🎤 Interviewer Follow-up Q10 of Q15

Bit Manipulation - Generate All Permutations Using Bitmask DP

Suppose you want to generate all permutations of n elements where elements can be repeated unlimited times. Which approach best handles this variant?

ABitmask DP with visited bits to prevent reuse

BRecursive backtracking with visited array to track usage

CSimple recursion without visited tracking, allowing repeats

DIterative DP with bitmask representing counts of each element

Step-by-Step Solution

Solution:

Step 1: Understand problem variant
Elements can be reused unlimited times, so visited bits cannot track usage.
Step 2: Identify suitable approach
Simple recursion without visited tracking allows repeats naturally.
Step 3: Why other approaches fail
Visited bits prevent reuse; recursive visited array disallows repeats; iterative DP with bitmask counts is complex and uncommon.
Final Answer:
Option C -> Option C
Quick Check:
Unlimited reuse is naturally handled by simple recursion without visited tracking [OK]

Quick Trick: Unlimited reuse needs no visited tracking [OK]

Common Mistakes:

MISTAKES

Trying to reuse visited bitmask for unlimited repeats

Trap Explanation:

PITFALL

Candidates incorrectly apply visited bitmask to problems allowing repeats.

Interviewer Note:

CONTEXT

Tests ability to adapt bitmask DP to variants with repeated elements

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