How should I practice Longest Substring with At Least K Repeating Characters?

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

Is Longest Substring with At Least K Repeating Characters 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.

Longest Substring with At Least K Repeating Characters

Bloomberg LP● MediumNEW GRADPHONE SCREEN

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Problem statement

Given a string s and an integer k, return the length of the longest substring in which every distinct character appears at least k times.

If no nonempty substring satisfies the condition, return 0.

Function

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

Examples

Example 1

s = "aaabb"k = 3return = 3

The substring aaa contains one distinct character exactly three times.

Example 2

s = "ababbc"k = 2return = 5

In ababb, a occurs twice and b occurs three times.

Example 3

s = "abc"k = 2return = 0

No character repeats twice in any substring.

Constraints

0 <= s.length <= 100000.
s contains only lowercase English letters.
1 <= k <= 100000.