How should I practice K-th Non-Repeating Character Index?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Bloomberg LP phone screen problems in FastPrep.

Is K-th Non-Repeating Character Index associated with Bloomberg LP?

FastPrep tags this as a Bloomberg LP phone screen coding practice problem when the problem catalog has that company and stage context.

K-th Non-Repeating Character Index

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Problem statement

Given a possibly empty string s and a positive integer k, scan characters from left to right and consider only characters whose total frequency in s is exactly one.

Return the zero-based index of the k-th such character. Return -1 when fewer than k non-repeating characters exist.

Character comparisons are case-sensitive. Every printable ASCII character, including spaces, digits, and symbols, participates normally.

Function

kthNonRepeatingIndex(s: String, k: int) → int

Examples

Example 1

s = "swiss"k = 2return = 2

The non-repeating characters in encounter order are w at index 1 and i at index 2.

Example 2

s = "a!a?b"k = 2return = 3

The unique characters are !, ?, and b. The second appears at index 3.

Example 3

s = ""k = 1return = -1

The empty string contains no character, so it has no first unique character.

Constraints

0 <= s.length <= 100000.
1 <= k <= 100000.
s contains printable ASCII characters.