[Solved] Suppose the problem is modified so that each element in the array can be... Which modification to the backtracking with bitmask memoization approach is necessary to correctly solve this variant? | Subsets & Combinations

Subsets & Combinations - Partition to K Equal Sum Subsets

Suppose the problem is modified so that each element in the array can be used multiple times to form the k equal sum subsets (i.e., unlimited reuse of elements). Which modification to the backtracking with bitmask memoization approach is necessary to correctly solve this variant?

AKeep bitmask but allow resetting bits after each recursive call

BSort ascending instead of descending to handle reuse properly

CUse the same code without changes because bitmask handles reuse implicitly

DRemove bitmask usage since elements can be reused; track counts instead

Step-by-Step Solution

Step 1: Understand reuse impact on state representation
Bitmask tracks used elements uniquely; with reuse allowed, usage state is not binary but counts.
Step 2: Modify approach accordingly
Bitmask must be removed or replaced by frequency counts to track how many times each element is used; otherwise, states are incorrect.
Final Answer:
Option D -> Option D
Quick Check:
Bitmask cannot represent multiple uses of same element [OK]

Quick Trick: Bitmask tracks usage once; reuse breaks this assumption [OK]

Common Mistakes:

MISTAKES

Trying to reuse bitmask for multiple uses
Ignoring state representation changes

Trap Explanation:

PITFALL

Bitmask memoization looks reusable but fails when elements can be reused multiple times

Interviewer Note:

CONTEXT

Tests candidate's understanding of state representation and problem variants

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More Subsets & Combinations Quizzes

Which modification to the backtracking with bitmask memoization approach is necessary to correctly solve this variant?

Step 1: Understand reuse impact on state representation

Step 2: Modify approach accordingly

Final Answer:

Quick Check:

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