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Longest Unique Messenger Substring | Dataford Interview Questions - Dataford - Ace your Interview

Longest Unique Messenger Substring

Medium

Coding

Asked at 1 company1ArraysHash TablesDynamic Programming

Also asked at

Problem

In Meta Messenger, you are given a message string s. Return the length of the longest contiguous substring that contains no repeated characters.

This is a standard string and sliding-window problem: scan the string once and maintain the largest valid window with all unique characters.

Formal Specification

Input: a string s
Output: an integer representing the maximum length of a substring of s with all distinct characters

Examples

Example 1

Input: s = "abcabcbb"
Output: 3
Explanation: The longest substring without repeating characters is "abc", which has length 3.

Example 2

Input: s = "bbbbb"
Output: 1
Explanation: Every substring longer than length 1 repeats the character "b".

Example 3

Input: s = "pwwkew"
Output: 3
Explanation: One valid answer is "wke". "pwke" is not valid because a substring must be contiguous.

Constraints

0 <= len(s) <= 5 * 10^4
s contains English letters, digits, symbols, and spaces
Your solution should run in linear time

Examples

Example 1

Inputs = "abcabcbb"Output3WhyThe longest substring without repeated characters is "abc".

Example 2

Inputs = "bbbbb"Output1WhyOnly one unique character can appear in any valid substring.

Example 3

Inputs = "pwwkew"Output3Why"wke" is a longest valid contiguous substring.

Constraints

0 <= len(s) <= 5 * 10^4
s consists of English letters, digits, symbols, and spaces
A linear-time solution is expected

Function Signature

def length_of_longest_substring(s):

Problem

In Meta Messenger, you are given a message string s. Return the length of the longest contiguous substring that contains no repeated characters.

This is a standard string and sliding-window problem: scan the string once and maintain the largest valid window with all unique characters.

Formal Specification

Input: a string s
Output: an integer representing the maximum length of a substring of s with all distinct characters

Examples

Example 1

Input: s = "abcabcbb"
Output: 3
Explanation: The longest substring without repeating characters is "abc", which has length 3.

Example 2

Input: s = "bbbbb"
Output: 1
Explanation: Every substring longer than length 1 repeats the character "b".

Example 3

Input: s = "pwwkew"
Output: 3
Explanation: One valid answer is "wke". "pwke" is not valid because a substring must be contiguous.

Constraints

0 <= len(s) <= 5 * 10^4
s contains English letters, digits, symbols, and spaces
Your solution should run in linear time

Examples

Example 1

Inputs = "abcabcbb"Output3WhyThe longest substring without repeated characters is "abc".

Example 2

Inputs = "bbbbb"Output1WhyOnly one unique character can appear in any valid substring.

Example 3

Inputs = "pwwkew"Output3Why"wke" is a longest valid contiguous substring.

Constraints

0 <= len(s) <= 5 * 10^4
s consists of English letters, digits, symbols, and spaces
A linear-time solution is expected

Function Signature

def length_of_longest_substring(s):

Practice Python

Python 3.10

Open on desktop for the full Python editor with syntax highlighting and autocomplete.

Up next

Longest Unique Message SubstringMedium

Longest Unique Messenger SubstringMedium

Longest Unique Message SubstringMedium

Next question

Longest Unique Messenger Substring

Medium

Coding

Asked at 1 company1ArraysHash TablesDynamic Programming

Also asked at

Problem

In Meta Messenger, you are given a message string s. Return the length of the longest contiguous substring that contains no repeated characters.

This is a standard string and sliding-window problem: scan the string once and maintain the largest valid window with all unique characters.

Formal Specification

Input: a string s
Output: an integer representing the maximum length of a substring of s with all distinct characters

Examples

Example 1

Input: s = "abcabcbb"
Output: 3
Explanation: The longest substring without repeating characters is "abc", which has length 3.

Example 2

Input: s = "bbbbb"
Output: 1
Explanation: Every substring longer than length 1 repeats the character "b".

Example 3

Input: s = "pwwkew"
Output: 3
Explanation: One valid answer is "wke". "pwke" is not valid because a substring must be contiguous.

Constraints

0 <= len(s) <= 5 * 10^4
s contains English letters, digits, symbols, and spaces
Your solution should run in linear time

Examples

Example 1

Inputs = "abcabcbb"Output3WhyThe longest substring without repeated characters is "abc".

Example 2

Inputs = "bbbbb"Output1WhyOnly one unique character can appear in any valid substring.

Example 3

Inputs = "pwwkew"Output3Why"wke" is a longest valid contiguous substring.

Constraints

0 <= len(s) <= 5 * 10^4
s consists of English letters, digits, symbols, and spaces
A linear-time solution is expected

Function Signature

def length_of_longest_substring(s):

Problem

In Meta Messenger, you are given a message string s. Return the length of the longest contiguous substring that contains no repeated characters.

This is a standard string and sliding-window problem: scan the string once and maintain the largest valid window with all unique characters.

Formal Specification

Input: a string s
Output: an integer representing the maximum length of a substring of s with all distinct characters

Examples

Example 1

Input: s = "abcabcbb"
Output: 3
Explanation: The longest substring without repeating characters is "abc", which has length 3.

Example 2

Input: s = "bbbbb"
Output: 1
Explanation: Every substring longer than length 1 repeats the character "b".

Example 3

Input: s = "pwwkew"
Output: 3
Explanation: One valid answer is "wke". "pwke" is not valid because a substring must be contiguous.

Constraints

0 <= len(s) <= 5 * 10^4
s contains English letters, digits, symbols, and spaces
Your solution should run in linear time

Examples

Example 1

Inputs = "abcabcbb"Output3WhyThe longest substring without repeated characters is "abc".

Example 2

Inputs = "bbbbb"Output1WhyOnly one unique character can appear in any valid substring.

Example 3

Inputs = "pwwkew"Output3Why"wke" is a longest valid contiguous substring.

Constraints

0 <= len(s) <= 5 * 10^4
s consists of English letters, digits, symbols, and spaces
A linear-time solution is expected

Function Signature

def length_of_longest_substring(s):

Practice Python

Python 3.10

Open on desktop for the full Python editor with syntax highlighting and autocomplete.

Up next

Longest Unique Message SubstringMedium

Longest Unique Messenger SubstringMedium

Longest Unique Message SubstringMedium

Next question