LCS ( Longest Common Subsequence ) of three strings | Java 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 ] ; 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 ] ; L [ m ] [ n ] [ o ] contains length of LCS for X [ 0. . n - 1 ] and Y [ 0. . m - 1 ] and Z [ 0. . o - 1 ] ; Driver program to test above function
public class LCS_3Strings { static int lcsOf3 ( String X , String Y , String Z , int m , int n , int o ) { int [ ] [ ] [ ] L = new int [ m + 1 ] [ n + 1 ] [ o + 1 ] ; for ( int i = 0 ; i <= m ; i ++ ) { for ( int j = 0 ; j <= n ; j ++ ) { for ( int k = 0 ; k <= o ; k ++ ) { if ( i == 0 j == 0 k == 0 ) L [ i ] [ j ] [ k ] = 0 ; else if ( X . charAt ( i - 1 ) == Y . charAt ( j - 1 ) && X . charAt ( i - 1 ) == Z . charAt ( k - 1 ) ) L [ i ] [ j ] [ k ] = L [ i - 1 ] [ j - 1 ] [ k - 1 ] + 1 ; else L [ i ] [ j ] [ k ] = Math . max ( Math . max ( L [ i - 1 ] [ j ] [ k ] , L [ i ] [ j - 1 ] [ k ] ) , L [ i ] [ j ] [ k - 1 ] ) ; } } } return L [ m ] [ n ] [ o ] ; } public static void main ( String args [ ] ) { String X = " AGGT12" ; String Y = "12TXAYB " ; String Z = "12XBA " ; int m = X . length ( ) ; int n = Y . length ( ) ; int o = Z . length ( ) ; System . out . println ( " Length ▁ of ▁ LCS ▁ is ▁ " + lcsOf3 ( X , Y , Z , m , n , o ) ) ; } }