[Leetcode] 3. Longest Substring Without Repeating Characters

중복 문자 없는 가장 긴 부분 문자열

3. Longest Substring Without Repeating Characters

https://leetcode.com/problems/longest-substring-without-repeating-characters/

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.

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# 풀이 1. 슬라이딩 윈도우와 투 포인터로 사이즈 조절
def lengthOfLongestSubstring(self, s: str) -> int:
    used = {}
    max_length = start = 0
    for index, char in enumerate(s):

        # 이미 등장했던 문자라면 'start' 위치 갱신
        if char in used and start <= used[char]:
            start = used[char] + 1

        else: # 최대 부분 문자열 길이 갱신
            max_length = max(max_length, index - start + 1)

        # 현재 문자의 위치 삽입
        used[char] = index
    return max_length