code: def _len_lcs(x, y):
      """Returns the length of the Longest Common Subsequence between two seqs.
  
      Source: http://www.algorithmist.com/index.php/Longest_Common_Subsequence
  
      Args:
        x: sequence of words
        y: sequence of words
  
      Returns
        integer: Length of LCS between x and y
      """
      table = _lcs(x, y)
      n, m = len(x), len(y)
      return table[n, m]
  
file_path: tensor2tensor/tensor2tensor/utils/rouge.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import numpy
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling a global function with example usage: _len_lcs(x, y) and returns: table