// Zorah Fung, CSE 143
// Runs the binary search algorithm on a list of TAs.

import java.util.*;

public class Search {
   public static void main(String[] args) {
      List<String> tas = new ArrayList<String>();
      tas.add("Natalie");
      tas.add("Aishwarya");
      tas.add("Shobhit");
      tas.add("Tyler");
      tas.add("Emily");
      tas.add("Karan");
      tas.add("Meredith");
      System.out.println(tas);
      Collections.sort(tas);
      System.out.println(tas);

      int meredith = binarySearch(tas, "Meredith");
      System.out.println(meredith);

      int shannon = binarySearch(tas, "Shannon");
      System.out.println(shannon);
   }

   // Returns the index of target in list using the binary search algorithm. If
   // target is not in list, returns -(insertion point + 1).
   // Pre: list is sorted in ascending order; result is undefined otherwise
   public static int binarySearch(List<String> list, String target) {
      return binarySearch(list, target, 0, list.size() - 1);
   }

   // Returns the index of target in l between min and max using the binary
   // search algorithm. If target is not in l, returns -(insertion point + 1).
   // Pre: l is sorted in ascending order; result is undefined otherwise
   private static int binarySearch(List<String> list, String target, int min,
         int max) {
      // base cases:
      // - only name we're looking for is left
      // - no names are left
      int mid = (min + max) / 2;

      int compare = target.compareTo(list.get(mid));

      if (compare == 0) { // found the target
         return mid;
      } else if (min > max) { // no names are left
         return -(min + 1); // or simply -1 but this gives more info
      } else if (compare > 0) {
         return binarySearch(list, target, mid + 1, max); // right side
      } else {
         return binarySearch(list, target, min, mid - 1); // left side
      }
   }
}