Longest Common Substring | DP | Java implementation of finding length of longest Common substring using Dynamic Programming ; Returns length of longest common substring of X [ 0. . m - 1 ] and Y [ 0. . n - 1 ] ; Create a table to store lengths of longest common suffixes of substrings . Note that LCSuff [ i ] [ j ] contains length of longest common suffix of X [ 0. . i - 1 ] and Y [ 0. . j - 1 ] . The first row and first column entries have no logical meaning , they are used only for simplicity of program ; To store length of the longest common substring ; Following steps build LCSuff [ m + 1 ] [ n + 1 ] in bottom up fashion ; Driver Code
class GFG { static int LCSubStr ( char X [ ] , char Y [ ] , int m , int n ) { int LCStuff [ ] [ ] = new int [ m + 1 ] [ n + 1 ] ; int result = 0 ; for ( int i = 0 ; i <= m ; i ++ ) { for ( int j = 0 ; j <= n ; j ++ ) { if ( i == 0 j == 0 ) LCStuff [ i ] [ j ] = 0 ; else if ( X [ i - 1 ] == Y [ j - 1 ] ) { LCStuff [ i ] [ j ] = LCStuff [ i - 1 ] [ j - 1 ] + 1 ; result = Integer . max ( result , LCStuff [ i ] [ j ] ) ; } else LCStuff [ i ] [ j ] = 0 ; } } return result ; } public static void main ( String [ ] args ) { String X = " OldSite : GeeksforGeeks . org " ; String Y = " NewSite : GeeksQuiz . com " ; int m = X . length ( ) ; int n = Y . length ( ) ; System . out . println ( LCSubStr ( X . toCharArray ( ) , Y . toCharArray ( ) , m , n ) ) ; } }