package pr02;

public class Percentile {
   
   private double[] list;
   private int size;
   private int capacity;
   
   public Percentile(int capacity) {
      this.capacity = capacity;
      list = new double[capacity];
      size = 0;
   }
   
   public int getSize() {
      return size;
   }
   
   public int getCapacity() {
      return capacity;
   }
   
   public boolean add(double value) {
      if (size >= capacity)
         return false;
      list[size] = value;
      size++;
      return true;
   }
   
   public int getRank(double value) {
      int count = 0;
      if (size == 0)
         return 0;
      for (int i=0;i<size;i++)
         if (value > list[i])
            count++;
      return (100*count)/size;
   }
   
   public double getPercentilePart2(int p) {
      if ((size == 0) || (p < 0) || (p > 100))
         return 0;
      for (int i=0;i<size;i++)
         if (checkPercentile(list[i], p))
            return list[i];
      return -1;                      // this should never happen
   }
   
   public double getPercentile(int p) {
      boolean foundFirst = false;
      double first = -1;
      if ((size == 0) || (p < 0) || (p > 100))
         return 0;
      for (int i=0;i<size;i++)
         if (checkPercentile(list[i], p)) {
            if (!foundFirst) {
               first = list[i];
               foundFirst = true;
            }
            else if (first != list[i])
               return (first + list[i])/2;
          }
      return first;
   }
   
   private boolean checkPercentile(double val, int p) {
        int count1 = countGreaterOrEqual(val);
        int count2 = countLessOrEqual(val);
        if ((100*count1)/(double)size < p)
           return false;
        if ((100*count2)/(double)size < 100-p)
           return false;
        return true;
   }
   
   private int countGreaterOrEqual(double val) {
      int count = 0;
      for (int i=0;i<size;i++)
         if (val >= list[i])
            count++;
      return count;
   }
   
   private int countLessOrEqual(double val) {
      int count = 0;
      for (int i=0;i<size;i++)
         if (val <= list[i])
            count++;
      return count;
   }
   
   public String toString() {
      StringBuilder sb = new StringBuilder();
      sb.append("Percentile with capacity " + capacity +
            " and size "+size + ": ");
      for (int i=0;i<size;i++)
         if (i < size - 1)
            sb.append(list[i] + ", ");
         else
            sb.append(list[i]);
      return sb.toString();
   }

}