// Time O(n*2^n)

// Space O(n*2^n)

// function poweset(array) {

// const subsets = [[]];

// for (let num of array) {

// const length = subsets.length;

// for (let i = 0; i < length; i++) {

// const currentSubset = subsets[i];

// subsets.push(currentSubset.concat(num));

// }

// }

// return subsets;

// }

// recursive solution

// runs in the same time/space complexity

function powerset(array, idx = null) {

if (idx === null) {

idx = array.length - 1;

}

if (idx < 0) {

return [[]];

}

const ele = array[idx];

const subsets = powerset(array, idx - 1);

const length = subsets.length;

for (let i = 0; i < length; i++) {

const currentSubset = subsets[i];

subsets.push(currentSubset.concat(ele));

}

return subsets;

}

const array = [];

console.log(powerset(array));