[Solved] You are given a list of candidate numbers (which may contain duplicates) and a target... Which algorithmic approach best guarantees finding all unique combinations without duplicates efficiently? | Subsets & Combinations

Subsets & Combinations - Combination Sum II (No Reuse, Duplicates)

You are given a list of candidate numbers (which may contain duplicates) and a target sum. You need to find all unique combinations where each candidate number is used at most once and the sum of the combination equals the target. Which algorithmic approach best guarantees finding all unique combinations without duplicates efficiently?

ABacktracking with sorting candidates, skipping duplicates at the same recursion level, and pruning branches when the candidate exceeds the remaining target

BGreedy algorithm that picks the largest candidates first until the target is met or exceeded

CDynamic programming subset-sum approach without handling duplicates explicitly

DBrute force recursion without sorting or duplicate checks, exploring all subsets

Step-by-Step Solution

Step 1: Understand problem constraints
The problem requires unique combinations without reuse and no duplicate results, so duplicates must be handled carefully.
Step 2: Identify suitable algorithm
Backtracking with sorting and skipping duplicates at the same recursion level ensures no repeated combinations. Early pruning avoids unnecessary recursion when candidates exceed the target.
Final Answer:
Option A -> Option A
Quick Check:
Sorting + duplicate skipping + pruning is the standard approach [OK]

Quick Trick: Sorting and skipping duplicates avoids repeated combinations [OK]

Common Mistakes:

MISTAKES

Using greedy misses some combinations
DP without duplicate handling outputs duplicates
Brute force is correct but inefficient and duplicates appear

Trap Explanation:

PITFALL

DP or brute force may seem correct but fail to handle duplicates properly or are inefficient.

Interviewer Note:

CONTEXT

Tests if candidate recognizes the need for sorting and duplicate skipping in backtracking.

Master "Combination Sum II (No Reuse, Duplicates)" in Subsets & Combinations

3 interactive learning modes - each teaches the same concept differently

Try It Solution Trace

More Subsets & Combinations Quizzes

Which algorithmic approach best guarantees finding all unique combinations without duplicates efficiently?

Step 1: Understand problem constraints

Step 2: Identify suitable algorithm

Final Answer:

Quick Check:

Want More Practice?