Longest Common Substring | DP | 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
function LCSubStr ( X , Y , m , n ) { var LCStuff = Array ( m + 1 ) . fill ( ) . map ( ( ) => Array ( n + 1 ) . fill ( 0 ) ) ; var result = 0 ; for ( i = 0 ; i <= m ; i ++ ) { for ( 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 = Math . max ( result , LCStuff [ i ] [ j ] ) ; } else LCStuff [ i ] [ j ] = 0 ; } } return result ; } var X = " " ; var Y = " " ; var m = X . length ; var n = Y . length ; document . write ( " " + LCSubStr ( X , Y , m , n ) ) ;