3.longest-substring-without-repeating-characters.py

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# @lc app=leetcode id=3 lang=python
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# [3] Longest Substring Without Repeating Characters
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# https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
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# algorithms
# Medium (27.53%)
# Total Accepted:    808.1K
# Total Submissions: 2.9M
# Testcase Example:  '"abcabcbb"'
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# Given a string, find the length of the longest substring without repeating
# characters.
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# Example 1:
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# Input: "abcabcbb"
# Output: 3
# Explanation: The answer is "abc", with the length of 3.
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# Example 2:
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# Input: "bbbbb"
# Output: 1
# Explanation: The answer is "b", with the length of 1.
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# Example 3:
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# Input: "pwwkew"
# Output: 3
# Explanation: The answer is "wke", with the length of 3.
# ⁠            Note that the answer must be a substring, "pwke" is a
# subsequence and not a substring.
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class Solution(object):
    def lengthOfLongestSubstring(self, s):
        """
        :type s: str
        :rtype: int
        """
        s_len = len(s)
        ans = 0
        hash_map = {}
        i = 0
        j = 0
        while j < s_len:
            if s[j] in hash_map.keys():
                i = max(hash_map[s[j]], i)
            ans = max(ans, j - i + 1)
            hash_map[s[j]] = j + 1
            j = j + 1
        return ans