Longest Substring Without Repeating CharactersGiven a string s find the length of the longest  substring without repeating characters.

This problem can be solved using the sliding window technique. Here are the steps in Python:

1. Initialize two pointers, start and end, to point to the beginning of the string. These pointers will define our current substring.

2. Initialize a dictionary, used_chars, to keep track of the characters we have seen and their latest positions.

3. While end is less than the length of the string, do the following:

   • If the character at end is not in used_chars, add it to used_chars and increment end.

   • If the character at end is in used_chars, move start to the right of the previous instance of the character at end and update its position in used_chars.

4. The length of the longest substring without repeating characters is the maximum length of the substring we have seen during this process.

Here is the Python code for the above steps:

def lengthOfLongestSubstring(s):
    start = max_length = 0
    used_chars = {}

    for i, char in enumerate(s):
        if char in used_chars and start <= used_chars[char]:
            start = used_chars[char] + 1
        else:
            max_length = max(max_length, i - start + 1)

        used_chars[char] = i

    return max_length

This function works by keeping track of the longest substring seen so far and the start of the current substring. When it sees a repeating character, it moves the start of the current substring to the right of the previous instance of the repeating character and updates the position of the repeating character. The length of the longest substring is updated whenever a longer substring is found.