package algs24;
import stdlib.*;
import java.util.Arrays;

public class FixedPQUnordered implements PQ {
  private int N;
  private double[] a;
  
  public FixedPQUnordered(int capacity)  { N = 0; a = new double[capacity+1]; } 
  public void toGraphviz()          { }
  public String toString ()         { return Arrays.toString(a).replaceAll(" 0\\.0", " ").replaceAll("\\[0\\.0", "[ ").replaceAll("\\.0", ""); }
  public int size()                 { return N; }
  public boolean isEmpty()          { return N == 0; }
  
  public void insert(double x) {
    if (x == 0) throw new Error ("No zeroes allowed");
    if (N >= a.length-1) throw new Error("Overflow");
    N++;
    a[N] = x;
  }
  private int minPosition() {
    if (N<=0) throw new Error("Underflow");
    int result = 1;
    for (int i=2; i<=N; i++) 
      if (a[i] < a[result]) result = i;
    return result;
  }
  public double min() {
    int m = minPosition(); 
    return a[m];
  }
  public double delMin() {
    int m = minPosition(); 
    double result = a[m];
    exch2(m, N);
    a[N] = 0.0;
    N--;
    return result;
  }
  private void exch2(int i, int j) {
    double oldi = a[i];
    double oldj = a[j];
    if (TestPQ.SHOW_STEPS) { StdOut.format("  exch(%2.0f,%2.0f)> %s\n", oldi, oldj, this); toGraphviz(); }
    a[i] = oldj;
    a[j] = oldi;
  }
}