leetcode Combination Sum II

题目链接

思路：

其实就是在递归的时候避免开始递归的点和现在的点是相同的就好。也就是代码

int k=i++;
            while(i<n&&candidates[i]==candidates[k])
            { i++; }

这里实现的东西。。

public class Solution {


    int [] candidates;
    int n;
    LinkedList<List<Integer>> result;
    LinkedList<Integer>temp;
    public List<List<Integer>> combinationSum2(int[] candidates, int target)  {
        Arrays.sort(candidates);
        this.candidates=candidates;
        n=candidates.length;
        result=new LinkedList<List<Integer>>();
        temp=new LinkedList<Integer>();
        help(0,target);
        return result;
    }

    void help(int start,int left)
    {
        int i=start;
        while(i<n)
        {
            int currentLeft=left-candidates[i];
            if(currentLeft<0)
            {
                return;
            }


            temp.add(candidates[i]);
            if(currentLeft>0)
            {
                int k=i+1;
                if(k<n)
                {
                    help(k,currentLeft);
                }

            }
            else// if(currentLeft==0)
            {

                result.add(new LinkedList<Integer>(temp));

            }
            temp.removeLast();
            int k=i++;public class Solution {


    int [] candidates;
    int n;
    LinkedList<List<Integer>> result;
    LinkedList<Integer>temp;
    public List<List<Integer>> combinationSum2(int[] candidates, int target)  {
        Arrays.sort(candidates);
        this.candidates=candidates;
        n=candidates.length;
        result=new LinkedList<List<Integer>>();
        temp=new LinkedList<Integer>();
        help(0,target);
        return result;
    }

    void help(int start,int left)
    {
        int i=start;
        while(i<n)
        {
            int currentLeft=left-candidates[i];
            if(currentLeft<0)
            {
                return;
            }


            temp.add(candidates[i]);
            if(currentLeft>0)
            {
                int k=i+1;
                if(k<n)
                {
                    help(k,currentLeft);
                }

            }
            else// if(currentLeft==0)
            {

                result.add(new LinkedList<Integer>(temp));

            }
            temp.removeLast();
            int k=i++;
            while(i<n&&candidates[i]==candidates[k])
            {
                i++;
            }
        }
        return;
    }

}
            while(i<n&&candidates[i]==candidates[k])
            {
                i++;
            }
        }
        return;
    }

}