Python: 1624. Largest Substring Between Two Equal Characters

 1624. Largest Substring Between Two Equal Characters

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.

同樣辦法，維持一個list，長度26，每個元素儲存的是第一個index of 那個字母

走過一次string，如果發現過去有某字母已經出現，則更新最大長度，否則initiate

class Solution:
    def maxLengthBetweenEqualCharacters(self, s: str) -> int:
        if len(set(s))==len(s):
            return -1
        # index list
        d=[-1]*26
        
        ans=0
        for i,x in enumerate(s):
            if d[ord(x)-97]>-1:
                ans=max(ans,i-d[ord(x)-97]-1)
            else:
                d[ord(x)-97]=i
                
        return ans