Following steps build L [ m + 1 ] [ n + 1 ] in bottom up fashion Note : L [ i ] [ j ] contains length of LCS of X [ 0. . i - 1 ] and Y [ 0. . j - 1 ]
for i in range ( m + 1 ) : NEW_LINE INDENT for j in range ( n + 1 ) : NEW_LINE INDENT if i == 0 or j == 0 : NEW_LINE INDENT L [ i ] [ j ] = 0 NEW_LINE DEDENT elif X [ i - 1 ] == Y [ j - 1 ] : NEW_LINE INDENT L [ i ] [ j ] = L [ i - 1 ] [ j - 1 ] + 1 NEW_LINE DEDENT else : NEW_LINE INDENT L [ i ] [ j ] = max ( L [ i - 1 ] [ j ] , L [ i ] [ j - 1 ] ) NEW_LINE DEDENT DEDENT DEDENT