46 DIY Subsets | leetcode/lintcode题解/算法学习笔记

public class Solution {
    public IList<IList<int>> Permute(int[] nums) {
        
        List<IList<int>> rst=new List<IList<int>>();
        
        if(nums==null)
        {
            return rst;
        }
        
        if(nums.Length==0)
        {
            rst.Add(new List<int>());
            return rst;
        }
        
        List<int> list=new List<int>();
        helper(rst,list,nums);
        
        return rst;
    }
    
    
    public void helper(List<IList<int>> rst, List<int> list, int[] nums)
    {
        if(list.Count==nums.Length)
        {
            rst.Add(new List<int>(list));
            return ;
        }
        
        for(int i=0;i<nums.Length;i++)
        {
            if(list.Contains(nums[i]))
            {
                continue;
            }
            
            list.Add(nums[i]);
            helper(rst,list,nums);
            list.RemoveAt(list.Count-1);
        }
        
    }
}