题目原址
https://leetcode.com/problems/subsets/description/
题目描述
Given a set of distinct integers, nums, return all possible subsets (the power set).
Note: The solution set must not contain duplicate subsets.
Example:
Input: nums = [1,2,3]
Output:
[
[3],
[1],
[2],
[1,2,3],
[1,3],
[2,3],
[1,2],
[]
]
解题思路
采用回溯来实现,即采用递归 + 循环的方法实现该题。其实就是dfs的一个应用。将数组中的元素一个一个放进集合中,每放进一个就要递归这个元素下面的元素。
AC代码
class Solution {
public List<List<Integer>> subsets(int[] nums) {
List<List<Integer>> ret = new ArrayList<List<Integer>>();
List<Integer> temp = new ArrayList<Integer>();
dfs(ret,temp,nums,0);
return ret;
}
public void dfs(List<List<Integer>> ret, List<Integer> temp, int[] nums, int j) {
// TODO Auto-generated method stub
ret.add(new ArrayList<Integer>(temp));
for(int i = j; i < nums.length; i++) {
temp.add(nums[i]);
dfs(ret,temp,nums,i + 1);
temp.remove(temp.size() - 1);
}
}
}
参考
https://blog.csdn.net/happyaaaaaaaaaaa/article/details/51604217