code: def _lcs(x, y):
      """
      Computes the length of the longest common subsequence (lcs) between two
      strings. The implementation below uses a DP programming algorithm and runs
      in O(nm) time where n = len(x) and m = len(y).
      Source: http://www.algorithmist.com/index.php/Longest_Common_Subsequence
  
      :param x: collection of words
      :param y: collection of words
      :returns table: dictionary of coord and len lcs
      """
      n, m = _get_index_of_lcs(x, y)
      table = dict()
      for i in range(n + 1):
          for j in range(m + 1):
              if i == 0 or j == 0:
                  table[i, j] = 0
              elif x[i - 1] == y[j - 1]:
                  table[i, j] = table[i - 1, j - 1] + 1
              else:
                  table[i, j] = max(table[i - 1, j], table[i, j - 1])
      return table
  
file_path: sumy/sumy/evaluation/rouge.py
imports: from __future__ import absolute_import
  from __future__ import division, print_function, unicode_literals
  from ..models.dom import Sentence
label_desc: Use image node_id 6 for calling a global function with example usage: _lcs(x, y) and returns: table