Leetcode Subsets

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

Note:

Elements in a subset must be in non-descending order.
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],
[]
]

本题采用位运算，首先把元素排好序，用sort函数，sort(nums.begin(),nums.end());

<span style="font-size:14px;">class Solution {
public:
vector<vector<int>> subsets(vector<int>& nums) {
int maxnum = 1<<nums.size();
vector<vector<int>> result;
sort(nums.begin(),nums.end());
for(int i=0; i<maxnum; i++)
{
vector<int> temp;
int k=0;
int idx = i;
while(idx>0)
{
if(idx&1)
{
temp.push_back(nums[k]);
}
k++;
idx = idx>>1;
}
result.push_back(temp);
}
return result;
}
};</span>