(java)leetcode-78:Subsets

Subsets

Given a set of distinct integers, nums, return all possible subsets.

Note: The solution set must not contain duplicate subsets.

For example,

If nums =

[1,2,3]

, a solution is:

[
[3],
[1],
[2],
[1,2,3],
[1,3],
[2,3],
[1,2],
[]
]

解题思路：
这道题是要找数组的所有子集。那想法跟上道题一样。区别就是在每次建一个新的list的时候，都将其存到List<List<Integer>>里面就行。

public class Solution {
public List<List<Integer>> result = new ArrayList<List<Integer>>();
public List<List<Integer>> subsets(int[] nums) {
List<Integer> com = new ArrayList<Integer>();
result.add(com);
addsub(0,nums,com);
return result;
}
public void addsub(int i,int[] nums,List<Integer> com)
{
int length = nums.length;
if(i < length)
{
for(int j = i;j<length;j++)
{
List<Integer> newcom = new ArrayList<Integer>();
newcom.addAll(com);
newcom.add(nums[j]);
result.add(newcom);
addsub(j+1,nums,newcom);
}
}
}
}