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* Problem Statement: Find all distinct, non-empty subsequence of given string in lexicographical order using recursive approach.

* What is subsequence?

* A Subsequence is sequence obtained by deleting some or no elements without changing the order of elements

* Example: Given a string = "abcd"

* 1. "abc" is a subsequence

* 2. "abd" is a subsequence

* 3. But "ba" is not a subsequence (because order is changed)

* What is lexicographical order?

* In simple terms, lexicographical order is dictionary order.

* Example: Given a string = "abcd"

* 1. "abc" will come before "abcd".

* 2. "abd" will come before "ac".

* References for meaning of subsequence & lexicographical:

* https://en.wikipedia.org/wiki/Subsequence

* https://en.wikipedia.org/wiki/Lexicographic_order

export const subsequence = (str, seq, low, output = []) => {

if (low <= str.length && str.length !== 0) {

output.push(seq)

}

for (let i = low; i < str.length; i++) {

subsequence(str, seq + str[i], i + 1, output)

}

return output

}