// Helene Martin, CSE 143
// Runs the binary search algorithm on a list of TAs.

import java.util.*;

public class Search {
   public static void main(String[] args) {
      ArrayList<String> tas = new ArrayList<String>();
      tas.add("Molly");
      tas.add("Connor");
      tas.add("Solai");
      tas.add("Todd");
      tas.add("Eden");
      tas.add("Kevin");
      tas.add("Mike");
      Collections.sort(tas);
      System.out.println(tas);

      int mike = binarySearch(tas, "Mike");
      System.out.println(mike);

      int hayley = binarySearch(tas, "Hayley");
      System.out.println(hayley);
   }

   // Returns the index of target in l 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
   public static int binarySearch(ArrayList<String> l, String target) {
      return binarySearch(l, target, 0, l.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(ArrayList<String> l, 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(l.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(l, target, mid + 1, max); // right side
      } else {
         return binarySearch(l, target, min, mid - 1); // left side
      }
   }
}