How should I practice Maximum Valid Substring Frequency?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Microsoft online assessment problems in FastPrep.

Is Maximum Valid Substring Frequency associated with Microsoft?

FastPrep tags this as a Microsoft online assessment coding practice problem when the problem catalog has that company and stage context.

Maximum Valid Substring Frequency

Microsoft● MediumFULLTIMEOA

Learn

Problem statement

Given a lowercase string text and three integers maxDistinct, minLength, and maxLength, return the maximum number of occurrences of any substring that satisfies both rules:

Its length is between minLength and maxLength, inclusive.
It contains at most maxDistinct distinct letters.

Occurrences may overlap. Return 0 when no substring satisfies the rules.

Function

maxSubstringFrequency(text: String, maxDistinct: int, minLength: int, maxLength: int) → int

Examples

Example 1

text = "aababcaab"maxDistinct = 2minLength = 3maxLength = 4return = 2

The substring aab appears twice, and it contains only the letters a and b.

Example 2

text = "aaaa"maxDistinct = 1minLength = 3maxLength = 3return = 2

The two length-three windows are both aaa, so overlapping occurrences produce frequency 2.

Example 3

text = "abcde"maxDistinct = 2minLength = 3maxLength = 3return = 0

Every length-three substring contains three distinct letters, so none is valid.

Constraints

1 <= text.length() <= 10^5.
text contains only lowercase English letters.
1 <= maxDistinct <= 26.
1 <= minLength <= maxLength <= min(26, text.length()).