Question
Given a set of candidate numbers (candidates) (with 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. Each number in candidates may only be used once in the combination.
Note:
All numbers (including target) will be positive integers. The solution set must not contain duplicate combinations.
Example 1:
Input: candidates = [10,1,2,7,6,1,5], target = 8,
A solution set is:
[
[1, 7],
[1, 2, 5],
[2, 6],
[1, 1, 6]
]
Example 2:
Input: candidates = [2,5,2,1,2], target = 5,
A solution set is:
[
[1,2,2],
[5]
]
Solution
DFS
Code
class Solution {
public List<List<Integer>> combinationSum2(int[] candidates, int target) {
Arrays.sort(candidates);
List<Integer> result = new ArrayList<>();
List<List<Integer>> results = new ArrayList<>();
dfs(candidates, 0, target, result, results);
return results;
}
public void dfs(int[] candidates, int start, int target, List<Integer> result, List<List<Integer>> results) {
if(target == 0) {
results.add(new ArrayList<>(result));
return;
}
if(target < 0) return;
for(int i=start; i<candidates.length; i++) {
if(i>start && candidates[i] == candidates[i-1]) continue;
if(result.size()>0 && result.get(result.size()-1) > candidates[i]) continue;
result.add(candidates[i]);
dfs(candidates, i+1, target-candidates[i], result, results);
result.remove(result.size()-1);
}
}
}