Algorithm

Procedures:

    For each nurse:

          1. consider each patient, if no patient can be served by her, go to step 4

          2. if one or more patients can be served by her, choose the patient leads

             to the smallest H value to serve.

          3. if the number of patients she already served reach the maximum number of

             patients she can serve 1 day, go step 4. Otherwise, go to step 1.

          4. a nurse finished her duty, change another nurse

Note: we assume that when deciding to serve a patient, first travel to his/her location,

      than wait for the patient to serve, after serving, the nurse has free time to

      serve other patients.