package top100liked

import (
	"fmt"
	"testing"
)

// https://leetcode.cn/problems/subsets/?envType=study-plan-v2&envId=top-100-liked

func subsets(nums []int) [][]int {
	res := [][]int{{}}
	var helper func(nums []int, length int, start int, r []int)
	helper = func(nums []int, length int, start int, r []int) {
		if len(r) == length {
			cp := make([]int, length)
			copy(cp, r)
			res = append(res, cp)
			return
		}
		for i := start; i < len(nums); i++ {
			r = append(r, nums[i])
			helper(nums, length, i+1, r)
			r = r[:len(r)-1]
		}
	}
	for i := range len(nums) {
		helper(nums, i+1, 0, []int{})
	}
	return res
}

func Test(t *testing.T) {
	fmt.Printf("%+v", subsets([]int{1, 2, 3}))
}