Answer: Red Hat OA Question 2024 August | Backtracking | on-campus

Solution: Combination Sum — Backtracking with Reuse Approach We use Backtracking. Since the same candidate can be reused unlimited times, when we recurse we pass the same index (not index+1). To avoid duplicate combinations, we always move forward in the candidates array — never go back. Sort the candidates (helps with early pruning). At each step, try adding a candidate to the current combination. If the remaining target becomes 0, we found a valid combination — add it to results. ...