Magic vowels python

magic.py

vowel = "aeiou"


def vpos(c):
    for i in range(5):
        if c == vowel[i]:
            return i
    return -1


def magical(s):
    l = len(s)
    previndex = [-1, -1, -1, -1, -1]

    leng = [0] * l
    ii = 0
    maxlen = 0

    while (s[ii] != 'a'):
        ii += 1
        if ii == l:
            return 0

    previndex[0] = ii
    leng[ii] = 1

    for i in range(ii + 1, l):
        if previndex[vpos(s[i])] >= 0:
            leng[i] = 1+leng[previndex[vpos(s[i])]]

        previndex[vpos(s[i])] = i

        if s[i] != 'a':
            if previndex[vpos(s[i])-1] >= 0:
                leng[i] = max(leng[i], 1+leng[previndex[vpos(s[i])-1]])

        maxlen = max(maxlen, leng[i])

    return maxlen


def main():
    s = "aeiaaioooaauuaeiou"
    print(s)
    print(magical(s))
    return 0

if __name__ == '__main__':
    main()