DAY 79 OF 90 · Two markers

Longest fresh stretch

Medium90 Days of Looping

Inputs

text is 0 to 16 lowercase letters (a to f).

Your tasks

Keep a left marker at 0 and best at 0.
Use a loop where right moves along text. While the letter at right already appears between left and right - 1, move left right by one.
Then update best with the window length right - left + 1.
Complete longestUnique so it returns best. Return it, do not print it.

Example

With text = "abcabcbb", longestUnique returns 3.

Rules

The stretch is neighbouring letters with no letter repeated.

Test data

TEST DATA 1: text is "abcabcbb"

TEST DATA 2: text is ""

Practice focus

Two pointers and sliding windows: loops that move two positions instead of one. Two pointers and sliding windows turn many quadratic answers into linear ones.

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