[Solved] Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sum to target. Each number in candidates may only be used once in the combination.

Question

Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sum to target.

Each number in candidates may only be used once in the combination.

Note: The solution set must not contain duplicate combinations.

Example 1:

Input: candidates = [10,1,2,7,6,1,5], target = 8
Output: 
[
[1,1,6],
[1,2,5],
[1,7],
[2,6]
]

Example 2:

Input: candidates = [2,5,2,1,2], target = 5
Output: 
[
[1,2,2],
[5]
]

Constraints:

  • 1 <= candidates.length <= 100
  • 1 <= candidates[i] <= 50
  • 1 <= target <= 30

Python Solution

class Solution:
    def combinationSum2(self, candidates: List[int], target: int) -> List[List[int]]:
        combinations = []
        candidates.sort()
        
        def solve(ind=0,curr_sum=0,curr_list=[]):
            if curr_sum==target:
                if curr_list not in combinations:
                    combinations.append(curr_list[:])
                return
            
            for i in range(ind,len(candidates)):
                if candidates[i]+curr_sum>target:
                    break
                solve(i+1,candidates[i]+curr_sum,curr_list+[candidates[i]])
        solve()
        return combinations
Abhishek Sharma
Abhishek Sharma

Started my Data Science journey in my 2nd year of college and since then continuously into it because of the magical powers of ML and continuously doing projects in almost every domain of AI like ML, DL, CV, NLP.

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