Combination Sum II

标签：算法   dfs   

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] 

public class Solution {
    public List<List<Integer>> combinationSum2(int[] num, int target) {
        LinkedList<List<Integer>> res=new LinkedList<List<Integer>>();
        LinkedList<Integer> list=new LinkedList<Integer>();
        if(num==null || num.length<=0) return res;
        Arrays.sort(num);
        dfs(0,0,target,num,list,res);
        HashSet set=new HashSet(res);
        res.clear();
        res.addAll(set);
        return res;
    }
    public void dfs(int start,int sum,int target,int[] num,LinkedList<Integer> list,List<List<Integer>> res){
        if(sum==target){
            LinkedList<Integer> l=new LinkedList<Integer>(list);
            res.add(l);
            return;
        }
        for(int i=start;i<num.length;i++){
            if(sum+num[i]>target) return;
            list.add(num[i]);
            dfs(i+1,sum+num[i],target,num,list,res);
            list.pollLast();
        }
    }
}

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Combination Sum II

标签：算法   dfs   

原文地址：http://blog.csdn.net/dutsoft/article/details/38640073