Longest substring without repeating characters

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        left = 0
        right = 0
        count = collections.defaultdict(int)
        res = 0

        while right < len(s):
            count[s[right]] += 1
            while count[s[right]] > 1:
                count[s[left]] -= 1
                left += 1
            res = max(res, right - left + 1)
            right += 1


        return res

Longest Substring Without Repeating Characters

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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.

 

Constraints:

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