[Leetcode] 0003. Longest Substring Without Repeating Characters

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內容目錄

Medium


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.

Python

				
					# time complexity: O(n)
# space complexity: O(min(m,n))
from collections import Counter


class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        chars = Counter()
        left = right = 0
        res = 0
        while right < len(s):
            r = s[right]
            chars[r] += 1
            while chars[r] > 1:
                l = s[left]
                chars[l] -= 1
                left += 1
            res = max(res, right - left + 1)
            right += 1
        return res


Input = "abcabcbb"
print(Solution().lengthOfLongestSubstring(Input))
				
			
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