How should I practice Shortest Substring with at Least K Distinct Characters?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Navan onsite interview problems in FastPrep.

Is Shortest Substring with at Least K Distinct Characters associated with Navan?

FastPrep tags this as a Navan onsite interview coding practice problem when the problem catalog has that company and stage context.

Shortest Substring with at Least K Distinct Characters

Navan● MediumFULLTIMEONSITE INTERVIEW

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Problem statement

Return the minimum length of a contiguous substring of text that contains at least k distinct characters. Return -1 if no such substring exists.

Function

shortestAtLeastKDistinct(text: String, k: int) → int

Examples

Example 1

text = "aabcbcdbca"k = 3return = 3

The substring abc has three distinct characters.

Example 2

text = "aaaa"k = 2return = -1

Only one distinct character exists.

Constraints

1 <= text.length <= 200000.
1 <= k <= 256.
For this exercise, assume text contains only ASCII characters; one character is one byte.