class_docstr: Calculate the Munkres solution to the classical assignment problem.
  See the module documentation for usage.
docstr: Cover each column containing a starred zero. If K columns are
  covered, the starred zeros describe a complete set of unique
  assignments. In this case, Go to DONE, otherwise, Go to Step 4.
docstr_tok: ["Cover","each","column","containing","a","starred","zero",".","If","K","columns","are","covered",",","the","starred","zeros","describe","a","complete","set","of","unique","assignments",".","In","this","case",",","Go","to","DONE",",","otherwise",",","Go","to","Step","4","."]
code: def __step3(self):
      """
      Cover each column containing a starred zero. If K columns are
      covered, the starred zeros describe a complete set of unique
      assignments. In this case, Go to DONE, otherwise, Go to Step 4.
      """
      n = self.n
      count = 0
      for i in range(n):
          for j in range(n):
              if self.marked[i][j] == 1:
                  self.col_covered[j] = True
                  count += 1
  
      if count >= n:
          step = 7  # done
      else:
          step = 4
  
      return step
  
imports: import sys
label_desc: Use image node_id 9 for calling the Munkres obj's underlying member method code with example usage: obj.__step3() and returns: step