Subsets

Description

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],
  []
]

Solution(javascript)

// 1: recursion
// const subsets = (nums = []) => {
//   const result = []
//   const aux = (index, current) => {
//     if (index === nums.length) {
//       result.push(current)
//     }
//     if (index < nums.length) {
//       aux(index + 1, current)
//       aux(index + 1, [...current, nums[index]])
//     }
//   }
//   aux(0, [])
//   return result
// }

// 2: Bit Manipulation
const subsets = (nums = []) => {
  const result = []
  const { length } = nums
  for (let i = 0; i < 2 ** length; i++) {
    const current = []
    for (let j = 0; j < length; j++) {
      if (i & (1 << j)) {
        current.push(nums[j])
      }
    }
    result.push(current)
  }
  return result
}