Longest-Substring-WithoutRepeatition

def lengthOfLongestSubstring(s):
    
    char_map = {}   # stores last index of each character
    left = 0
    max_length = 0
    
    for right in range(len(s)):
        
        # If character is already seen, move left pointer
        if s[right] in char_map:
            left = max(left, char_map[s[right]] + 1)
        
        # Update last seen index
        char_map[s[right]] = right
        
        # Update maximum length
        max_length = max(max_length, right - left + 1)
    
    return max_length


# Main program
s = input("Enter a string: ")

result = lengthOfLongestSubstring(s)

print("Length of longest substring without repeating characters:", result)