1. Problem Statement (Simple Explanation): You are given: An array candidates (may contain duplicates ). An integer target. You must return all unique combinations of numbers from candidates such that: The sum of the chosen numbers equals target. Each number can be used at most once in each combination. The result must not contain duplicate combinations . Return combinations in any order. 2. Examples: Example 1: Input: candidates = [10,1,2,7,6,1,5] target = 8 Possible unique combinations: [1,1,6] [1,2,5] [1,7] [2,6] Output: [ [1,1,6], [1,2,5], [1,7], [2,6] ] Example 2: Input: candidates = [2,5,2,1,2] target = 5 Valid unique combinations: [1,2,2] [5] Output: [ [1,2,2], [5] ] 3. Key Differences vs. Combination Sum (Problem 39): Here, each candidate can be used at most once . candidates may contain duplicates , but the result must have...
1. Problem Statement (Simple Explanation): You are given: An array of distinct positive integers candidates. A positive integer target. You must find all unique combinations of numbers from candidates such that: The sum of the chosen numbers equals target. You can use the same number unlimited times . Two combinations are considered different if the count of at least one number differs. Return all combinations (order of combinations and order inside each combination does not matter). The number of unique combinations is guaranteed to be < 150. 2. Examples: Example 1: Input: candidates = [2,3,6,7], target = 7 Valid combinations: 2 + 2 + 3 = 7 → [2,2,3] 7 = 7 → [7] Output: [[2,2,3],[7]] Example 2: Input: candidates = [2,3,5], target = 8 Valid combinations: 2 + 2 + 2 + 2 = 8 → [2,2,2,2] 2 + 3 + 3 = 8 → [2,3,3] 3 + 5 = 8 → [3,5] Output: [[2,2,2,2],[2,3,3],[3,5]]...