Coding (Algo)

Strings and window state: track a moving substring while preserving character constraints

Strings and window state: Given a string s, return the length of its longest contiguous substring containing no repeated characters.

Input: A JSON object { "s": string }.

Output: A JSON integer representing the maximum substring length.

Constraints:

0 <= s.length <= 100000
Compare characters case-sensitively
The empty string returns 0

Read one JSON value from stdin and print exactly one JSON-serialized answer to stdout with no extra text.

Difficulty: MEDIUM. Variant: 17. Favor a pragmatic solution that is easy to ship, read, and adapt.

Practice context

This coding (algo) exercise trains prompt interpretation, explicit assumptions, a concrete response, and a concise explanation of the decisions made. It is marked medium difficulty.

The signed-in workspace provides the tools required by the round, such as recording, code execution, diagrams, structured notes, or evidence p

What this task practices

This coding (algo) exercise trains the same sequence expected in an interview: understand the prompt, make assumptions explicit, produce a concrete answer, and explain the decisions behind it. The task is marked medium difficulty. The private workspace adds the tools required by this round, such as recording, code execution, diagrams, evidence panels, or structured notes. It also preserves the attempt so later feedback can be compared with previous work. Evaluation is based on task-specific criteria and the candidate seniority selected in the preparation path. Public pages never expose the reference solution, hidden tests, evaluator instructions, or another candidate’s work.