This code calculates the length of the LCS between two strings. It also deals with Thai digits and roman digits.

lcs_len_th.py

def to_roman(a):
    if a >= '๐' and a <= '๙':
        return chr(ord(a) - ord('๐') + ord('0'))
    return a

def is_same_digit(a,b):
    if a < '0' and a > '9':
        return False

    aa = to_roman(a)
    bb = to_roman(b)
    return aa == bb

def lcs_len(s,t):
    n = len(s)
    m = len(t)
    
    tab = []
    tab.append([])

    for j in range(m+1):
        tab[0].append(0)

    for i in range(1,n+1):
        tab.append([])
        
        tab[i].append(0)

        for j in range(1,m+1):
            diag = tab[i-1][j-1]
            if s[i-1] == t[j-1] or (is_same_digit(s[i-1],t[j-1])):
                diag += 1
            tab[i].append(max(tab[i-1][j], tab[i][j-1], diag))

    return tab[n][m]