Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where
the candidate numbers sums to T.
Each number in C may only be used once in the combination.
Note:
- All numbers (including target) will be positive integers.
- Elements in a combination (a1, a2,
… , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤
… ≤ ak). - The solution set must not contain duplicate combinations.
For example, given candidate set 10,1,2,7,6,1,5
and target 8
,
A solution set is:
[1, 7]
[1, 2, 5]
[2, 6]
[1, 1, 6]
原题链接:https://oj.leetcode.com/problems/combination-sum-ii/
与之前一题的区别在于每个数字只能使用一次。故需在递归的时候直接使用下一个数字。
public class CombinationSumII { public static void main(String[] args) { List<List<Integer>> list = new CombinationSumII().combinationSum2(new int[]{10,1,2,7,6,1,5},8); for(List<Integer> li : list){ for(Integer i : li) System.out.print(i + "\t"); System.out.println(); } } private List<Integer> list = new ArrayList<Integer>(); private List<List<Integer>> result = new ArrayList<List<Integer>>(); public List<List<Integer>> combinationSum2(int[] num, int target) { if(num.length == 0) return result; Arrays.sort(num); dfs(num,target,0); return result; } public void dfs(int[] candidates,int target,int index){ if(target < 0) return; if(target == 0){ result.add(new ArrayList<Integer>(list)); return; } for(int i=index;i<candidates.length;i++){ if(i>index && candidates[i] == candidates[i-1]) continue; list.add(candidates[i]); dfs(candidates,target-candidates[i],i+1); list.remove(list.size()-1); } } }
时间: 2024-11-05 15:49:12