Longest common subsequence of 3+ strings

Question

I am trying to find the longest common subsequence of 3 or more strings. The Wikipedia article has a great description of how to do this for 2 strings, but I\'m a little uns

Answer 1

Here is a link to the solution view explanation here output is Length of LCS is 2

 # Python program to find 
 # LCS of three strings 

 # Returns length of LCS 
 # for X[0..m-1], Y[0..n-1] 
 # and Z[0..o-1] 
def lcsOf3(X, Y, Z, m, n, o): 

    L = [[[0 for i in range(o+1)] for j in range(n+1)] 
        for k in range(m+1)] 

    ''' Following steps build L[m+1][n+1][o+1] in 
    bottom up fashion. Note that L[i][j][k] 
    contains length of LCS of X[0..i-1] and 
    Y[0..j-1] and Z[0.....k-1] '''
   for i in range(m+1): 
    for j in range(n+1): 
        for k in range(o+1): 
            if (i == 0 or j == 0 or k == 0): 
                L[i][j][k] = 0

            elif (X[i-1] == Y[j-1] and
                  X[i-1] == Z[k-1]): 
                L[i][j][k] = L[i-1][j-1][k-1] + 1

            else: 
                L[i][j][k] = max(max(L[i-1][j][k], 
                L[i][j-1][k]), 
                                L[i][j][k-1]) 

      # L[m][n][o] contains length of LCS for 
      # X[0..n-1] and Y[0..m-1] and Z[0..o-1] 
    return L[m][n][o] 

  # Driver program to test above function 

X = 'AGGT12'
Y = '12TXAYB'
Z = '12XBA'

m = len(X) 
n = len(Y) 
o = len(Z) 

print('Length of LCS is', lcsOf3(X, Y, Z, m, n, o)) 

# This code is contributed by Soumen Ghosh.