Python C++ bitmask解Leetcode 1371 Find the Longest Substring Containing ...

Python C++ bitmask解Leetcode 1371  Find the Longest Substring Containing Vowels in Even Counts

建構一個容器first_seen[32]（5個母音考慮2**5=32），它表示第一次看到的32不同bmask的索引

[Python code請進]

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Build a container first_seen[32] (5 vowels to consider 2**5=32) which denotes the index for 32 different bmask first seen

[codes on Leetcode]https://leetcode.com/problems/find-the-longest-substring-containing-vowels-in-even-counts/solutions/5788042/prefix-sum-with-xor-for-bit-mask-11-ms-beats-99-53/

[bit/ bitmask play list]https://www.youtube.com/watch?v=Hw1fnQA8Nk8&list=PLYRlUBnWnd5K8FlzJ6tOswqQcsk7R1Duh

class Solution:
    def findTheLongestSubstring(self, s: str) -> int:
        vow=[-1]*26
        vow[0]=0
        vow[ord('e')-ord('a')]=1
        vow[ord('i')-ord('a')]=2
        vow[ord('o')-ord('a')]=3
        vow[ord('u')-ord('a')]=4
        n=len(s)
        first_seen=[-1]*32
        first_seen[0]=0
        curr=0
        Len=0
        for i in range(n):
            x=vow[ord(s[i])-ord('a')]
            if x!=-1: curr^=(1<<x)
            if first_seen[curr]==-1: first_seen[curr]=i+1
            Len=max(Len, i+1-first_seen[curr])
        return Len