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Longest Substring without Repeating Characters

Explore how to solve the longest substring without repeating characters problem by applying the sliding window pattern. Understand the problem constraints, and learn to implement an efficient solution that handles large input strings. This lesson develops your skills in substring handling and pattern recognition critical for coding interviews.

Statement

Given a string, str, return the length of the longest substring without repeating characters.

Constraints:

  • 11 \leq str.length 105\leq 10^5
  • str consists of English letters, digits, and spaces.

Examples

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Understand the problem

Let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps us to check if you’re solving the correct problem:

Longest Substring Without Repeating Characters

1.

What should be the output if the following string is given as an input?

s = “conceptoftheday”

A.

8

B.

6

C.

5

D.

13


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Figure it out!

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Sequence - Vertical
Drag and drop the cards to rearrange them in the correct sequence.

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Try it yourself

Implement your solution in the following coding playground:

Java
usercode > Main.java
import java.util.*;
public class Main{
public static int findLongestSubstring(String str) {
// Replace this placeholder return statement with your code
return -1;
}
}
Longest Substring without Repeating Characters