Subsets

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) {
        vector<vector<int>> out = {{}};
        for (int x : nums) {
            int sz = out.size();
            for (int i = 0; i < sz; ++i) {
                out.push_back(out[i]);
                out.back().push_back(x);
            }
        }
        return out;
    }
};

func subsets(nums []int) [][]int {
    out := [][]int{{}}
    for _, x := range nums {
        sz := len(out)
        for i := 0; i < sz; i++ {
            cp := make([]int, len(out[i]), len(out[i])+1)
            copy(cp, out[i])
            cp = append(cp, x)
            out = append(out, cp)
        }
    }
    return out
}

from typing import List

class Solution:
    def subsets(self, nums: List[int]) -> List[List[int]]:
        out: List[List[int]] = [[]]
        for x in nums:
            out.extend([sub + [x] for sub in out])
        return out

function subsets(nums) {
    const out = [[]];
    for (const x of nums) {
        const sz = out.length;
        for (let i = 0; i < sz; i++) {
            out.push([...out[i], x]);
        }
    }
    return out;
}

class Solution {
    public List<List<Integer>> subsets(int[] nums) {
        List<List<Integer>> out = new ArrayList<>();
        out.add(new ArrayList<>());
        for (int x : nums) {
            int sz = out.size();
            for (int i = 0; i < sz; i++) {
                List<Integer> cp = new ArrayList<>(out.get(i));
                cp.add(x);
                out.add(cp);
            }
        }
        return out;
    }
}

function subsets(nums: number[]): number[][] {
    const out: number[][] = [[]];
    for (const x of nums) {
        const sz = out.length;
        for (let i = 0; i < sz; i++) {
            out.push([...out[i], x]);
        }
    }
    return out;
}