[leetcode] combination sum

Given a set of candidate numbers (C) (without duplicates) and a target number (T),
find all unique combinations in C where the candidate numbers sums to T.

The same repeated number may be chosen from C unlimited number of times.

Note:
All numbers (including target) will be positive integers.
The solution set must not contain duplicate combinations.
For example, given candidate set [2, 3, 6, 7] and target 7,
A solution set is:
[
[7],
[2, 2, 3]
]

• 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

  public static List<List<Integer>> combinationSum(int[] candidates, int target) { List<List<Integer>> lists = new LinkedList<>(); List<Integer> list = new LinkedList<>(); find(candidates, 0, target, list, lists); return lists; } public static void (int[] candidates, int start, int target, List<Integer> list, List<List<Integer>> lists) { if (target < 0) { return; } if (target == 0) { lists.add(new LinkedList<>(list)); return; } for (int i = start; i < candidates.length; i++) { if (candidates[i] <= target) { list.add(candidates[i]); find(candidates, i, target - candidates[i], list, lists); list.remove(list.size() - 1); } } }