Given a set of candidate numbers (candidates) (without duplicates) and a target number (target),
find all unique combinations in candidates where the candidate numbers sums to target.
The same repeated number may be chosen from candidates unlimited number of times.
Note:
All numbers (including target) will be positive integers.
The solution set must not contain duplicate combinations.
Example 1:
Input: candidates = [2,3,6,7], target = 7,
A solution set is:
[
[7],
[2,2,3]
]
public List<List<Integer>> combinationSum(int[] candidates, int target) {
List<List<Integer>> result = new ArrayList<>();
backtrack(0, target, candidates, 0, new ArrayList<Integer>(), result);
return result;
}
public void backtrack(int curr, int target, int[] candidates, int index, ArrayList<Integer> temp, List<List<Integer>> result) {
if(curr >= target) {
if(curr == target) result.add(new ArrayList(temp));
return;
}
for(int i = index; i < candidates.length; i++) {
temp.add(candidates[i]);
backtrack(curr + candidates[i], target, candidates, i, temp, result);
temp.remove(temp.size()-1);
}
}