Longest Substring Without Repeating Characters Program (Leetcode)

Longest Substring Without Repeating Characters (Leetcode):

Given a string s, find the length of the longest substring without repeating characters.

Example 1:

Input: s = "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.

Example 2:

Input: s = "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.

Example 3:

Input: s = "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.

Example 4:

Input: s = ""
Output: 0

 

Constraints:

• 0 <= s.length <= 5 * 104
• s consists of English letters, digits, symbols, and spaces.

dict = {}
length = 0
start = 0
        
for i in range(len(s)):
        if s[i] in dict:
                start = max(start, dict[s[i]] + 1)
        if length < i - start + 1:
                length = i - start + 1
        dict[s[i]] = i
        
print(length)