describe

Given a string s, return the length of the longest substring between two equal characters, excluding the two characters. If there is no such substring return -1.

A substring is a contiguous sequence of characters within a string.

Example 1:

Input: s = "aa"
Output: 0
Explanation: The optimal substring here is an empty substring between the two 'a's.	
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Example 2:

Input: s = "abca"
Output: 2
Explanation: The optimal substring here is "bc".
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Example 3:

Input: s = "cbzxy"
Output: -1
Explanation: There are no characters that appear twice in s.
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Example 4:

Input: s = "cabbac"
Output: 4
Explanation: The optimal substring here is "abba". Other non-optimal substrings include "bb" and "".
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Note:

1 <= s.length <= 300
s contains only lowercase English letters.
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parsing

If there is no such thing, return -1. If there is no such thing, return -1. If there is no such thing, return -1. If the length of value in count is greater than 1, find the farthest distance. After the traversal, you can get the answer.

answer

class Solution(object):
    def maxLengthBetweenEqualCharacters(self, s):
        """
        :type s: str
        :rtype: int
        """
        if len(set(s)) == len(s):
            return -1
        count = {}
        for i,c in enumerate(s):
            if c not in count:
                count[c] = [i]
            else:
                count[c].append(i)
        r = -1
        for k,v in count.items():
            if len(v) > 1:
                r = max( r, v[-1]-v[0]-1)
        return r         	      
		
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The results

Runtime: 16 ms, Faster than 84.87% of Python online submissions for Largest Substring Between Two Equal Characters. Memory Usage: Each node in the Python online submission for Largest Substring Between Two Equal Characters.Copy the code

Original link: leetcode.com/problems/la…

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