docs: public void writeProblemsToHDFS(List<Frontier> problems) throws IOException {
          FileSystem fs = FileSystem.get(configuration);
          log.info("hdfsFileRoot = " + hdfsFileRoot);
  
          StringBuilder sb = new StringBuilder();
          for (Frontier problem : problems) {
              SCXMLGapper gapper = new SCXMLGapper();
              Map<String, String> decomposition = gapper.decompose(problem, stateMachineText);
              String problemString = decomposition.get("target") + "|" + decomposition.get("variables") + "|";
  
              sb.append(problemString.replace("\n", "").replace("\t", "").replace("\r", ""));
              sb.append("\n");
          }
  
          try (FSDataOutputStream out = fs.create(mapperInputFilePath)) {
              out.write(sb.toString().getBytes());
          } catch (IOException e) {
              log.error("Problem writing " + mapperInputFilePath + " prior to MR job execution");
          }
      }