Leetcode - Longest Substring Without Repeating Characters Solution
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.
Solution in Python3
class Solution:
def lengthOfLongestSubstring(self, s: str) -> int:
best = 0
non_unique = -1
seen = {}
for index,char in enumerate(s):
last_seen = seen.get(char, -1)
non_unique = max(non_unique, last_seen)
best = max(index-non_unique, best)
seen[char] = index
return best