Combination Sum II
Difficulty: Medium
Category: DSA
Topics: Array, Backtracking
Asked at: Amazon, Uber, Microsoft, ByteDance
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`