Bird
Raised Fist0

Which of the following problems CANNOT be solved using the backtracking approach designed for Combination Sum II (no reuse, duplicates allowed)?

easy🔍 Pattern Recognition Q2 of Q15
Subsets & Combinations - Combination Sum II (No Reuse, Duplicates)
Which of the following problems CANNOT be solved using the backtracking approach designed for Combination Sum II (no reuse, duplicates allowed)?
AFind all unique combinations of numbers summing to target, each number used once
BFind all unique combinations summing to target with unlimited reuse of elements
CFind all permutations of a list of numbers with duplicates allowed
DFind all subsets of a set with unique elements
Step-by-Step Solution
Solution:

  1. Step 1: Understand Combination Sum II constraints

    Combination Sum II requires no reuse of elements and handles duplicates by skipping.

  2. Step 2: Analyze each option

    Find all unique combinations summing to target with unlimited reuse of elements requires unlimited reuse, which breaks the no reuse constraint and needs a different approach.

  3. Final Answer:

    Option B -> Option B

  4. Quick Check:

    Unlimited reuse is incompatible with Combination Sum II backtracking [OK]
Quick Trick: Unlimited reuse breaks no-reuse backtracking [OK]
Common Mistakes:
MISTAKES
  • Confusing permutations with combinations
  • Assuming unlimited reuse fits no-reuse pattern
Trap Explanation:
PITFALL
  • Candidates often think backtracking can handle unlimited reuse without modification, but skipping duplicates and no reuse are core to this pattern.
Interviewer Note:
CONTEXT
  • Tests anti-pattern recognition and understanding of problem constraints.
Master "Combination Sum II (No Reuse, Duplicates)" in Subsets & Combinations

3 interactive learning modes - each teaches the same concept differently

Try ItSolutionTrace

Want More Practice?

15+ quiz questions · All difficulty levels · Free

Free Signup - Practice All Questions
More Subsets & Combinations Quizzes
Combination Sum (Reuse Allowed) - Combination Sum (Reuse Allowed) - Quiz 4medium Combination Sum III (K Numbers to N) - Combination Sum III (K Numbers to N) - Quiz 15hard Combinations (Choose K from N) - Combinations (Choose K from N) - Quiz 8hard Count Number of Max Bitwise-OR Subsets - Count Number of Max Bitwise-OR Subsets - Quiz 2easy Count of Subsets With Sum K - Count of Subsets With Sum K - Quiz 11easy Letter Case Permutation - Letter Case Permutation - Quiz 6medium Matchsticks to Square - Matchsticks to Square - Quiz 6medium Number of Valid Words for Each Puzzle - Number of Valid Words for Each Puzzle - Quiz 9hard Partition to K Equal Sum Subsets - Partition to K Equal Sum Subsets - Quiz 9hard Subsets - Subsets - Quiz 4medium