Longest Substring Without Repeating Characters [Solution]

Here’s a Python implementation of the length_of_longest_substring function to find the length of the longest substring without repeating characters:

def length_of_longest_substring(s: str) -> int:
    """
    Find the length of the longest substring without repeating characters.

    Parameters:
    - s: Input string.

    Returns:
    - int: Length of the longest substring without repeating characters.
    """
    char_index_map = {}  # Map to store the index of each character in the substring
    start_index = 0  # Starting index of the current substring
    max_length = 0  # Length of the longest substring without repeating characters

    for i, char in enumerate(s):
        if char in char_index_map and char_index_map[char] >= start_index:
            # If the character is repeated and its index is within the current substring
            start_index = char_index_map[char] + 1

        # Update the index of the character in the substring
        char_index_map[char] = i

        # Update the length of the longest substring
        max_length = max(max_length, i - start_index + 1)

    return max_length

# Example usage:
s1 = "abcabcbb"
result1 = length_of_longest_substring(s1)
print(result1)  # Output: 3

s2 = "bbbbb"
result2 = length_of_longest_substring(s2)
print(result2)  # Output: 1

s3 = "pwwkew"
result3 = length_of_longest_substring(s3)
print(result3)  # Output: 3

s4 = "abcde"
result4 = length_of_longest_substring(s4)
print(result4)  # Output: 5

This solution uses a sliding window approach to efficiently find the length of the longest substring without repeating characters.

Time Complexity:

The time complexity is O(n), where n is the length of the input string.

Space Complexity:

The space complexity is O(min(m, n)), where m is the size of the character set (in this case, lowercase English letters).