// Exercise 2.5.27 (Solution published at http://algs4.cs.princeton.edu/)
package algs21;
import stdlib.*;
import java.util.Comparator;
/* ***********************************************************************
 *  Compilation:  javac Insertion.java
 *  Execution:    java Insertion < input.txt
 *  Dependencies: StdOut.java StdIn.java
 *  Data files:   http://algs4.cs.princeton.edu/21sort/tiny.txt
 *                http://algs4.cs.princeton.edu/21sort/words3.txt
 *
 *  Sorts a sequence of strings from standard input using insertion sort.
 *
 *  % more tiny.txt
 *  S O R T E X A M P L E
 *
 *  % java Insertion < tiny.txt
 *  A E E L M O P R S T X                 [ one string per line ]
 *
 *  % more words3.txt
 *  bed bug dad yes zoo ... all bad yet
 *
 *  % java Insertion < words3.txt
 *  all bad bed bug dad ... yes yet zoo   [ one string per line ]
 *
 *************************************************************************/

public class Insertion {

  // use natural order and Comparable interface
  public static <T extends Comparable<? super T>> void sort(T[] a) {
    int N = a.length;
    for (int i = 0; i < N; i++) {
      for (int j = i; j > 0 && less(a[j], a[j-1]); j--) {
        exch(a, j, j-1);
      }
      //assert isSorted(a, 0, i);
    }
    //assert isSorted(a);
  }

  // use a custom order and Comparator interface - see Section 3.5
  public static <T> void sort(T[] a, Comparator<? super T> c) {
    int N = a.length;
    for (int i = 0; i < N; i++) {
      for (int j = i; j > 0 && less(c, a[j], a[j-1]); j--) {
        exch(a, j, j-1);
      }
      assert isSorted(a, c, 0, i);
    }
    assert isSorted(a, c);
  }

  // return a permutation that gives the elements in a[] in ascending order
  // do not change the original array a[]
  public static <T extends Comparable<? super T>> int[] indexSort(T[] a) {
    int N = a.length;
    int[] index = new int[N];
    for (int i = 0; i < N; i++)
      index[i] = i;

    for (int i = 0; i < N; i++)
      for (int j = i; j > 0 && less(a[index[j]], a[index[j-1]]); j--)
        exch(index, j, j-1);

    return index;
  }

  /* *********************************************************************
   *  Helper sorting functions
   ***********************************************************************/

  // is v < w ?
  private static <T extends Comparable<? super T>> boolean less(T v, T w) {
    if (COUNT_OPS) DoublingTest.incOps ();
    return (v.compareTo(w) < 0);
  }

  // exchange a[i] and a[j]
  private static <T> void exch(T[] a, int i, int j) {
    if (COUNT_OPS) DoublingTest.incOps ();
    T swap = a[i];
    a[i] = a[j];
    a[j] = swap;
  }
  
  
  // is v < w ?
  private static <T> boolean less(Comparator<? super T> c, T v, T w) {
    if (COUNT_OPS) DoublingTest.incOps ();
    return (c.compare(v, w) < 0);
  }

  // exchange a[i] and a[j]  (for indexSort)
  private static void exch(int[] a, int i, int j) {
    if (COUNT_OPS) DoublingTest.incOps ();
    int swap = a[i];
    a[i] = a[j];
    a[j] = swap;
  }

  /* *********************************************************************
   *  Check if array is sorted - useful for debugging
   ***********************************************************************/
  private static <T extends Comparable<? super T>> boolean isSorted(T[] a) {
    return isSorted(a, 0, a.length - 1);
  }

  // is the array sorted from a[lo] to a[hi]
  private static <T extends Comparable<? super T>> boolean isSorted(T[] a, int lo, int hi) {
    for (int i = lo + 1; i <= hi; i++)
      if (less(a[i], a[i-1])) return false;
    return true;
  }

  private static <T> boolean isSorted(T[] a, Comparator<? super T> c) {
    return isSorted(a, c, 0, a.length - 1);
  }

  // is the array sorted from a[lo] to a[hi]
  private static <T> boolean isSorted(T[] a, Comparator<? super T> c, int lo, int hi) {
    for (int i = lo + 1; i <= hi; i++)
      if (less(c, a[i], a[i-1])) return false;
    return true;
  }

  // print array to standard output
  private static <T> void show(T[] a) {
    StdOut.println(java.util.Arrays.toString(a));
  }

  // test code
  private static boolean COUNT_OPS = false;
  public static void main(String[] args) {
    StdIn.fromString ("S O R T E X A M P L E");
    //StdIn.fromFile ("data/tiny.txt");
    //StdIn.fromFile ("data/cards.txt");
    //StdIn.fromFile ("data/words3.txt");

    String[] a = StdIn.readAllStrings();
    //StdRandom.shuffle (a);
    //show(a);
    //StdOut.println ("----------------");
    sort(a);
    show(a);

    COUNT_OPS = true;
    DoublingTest.run (2000, 6, N -> ArrayGenerator.integerRandomUnique (N),      (Integer[] x) -> sort (x));
    //DoublingTest.run (2000, 6, N -> ArrayGenerator.integerRandom (N, 2),             (Integer[] x) -> sort (x));
    //DoublingTest.run (2000, 6, N -> ArrayGenerator.integerPartiallySortedUnique (N), (Integer[] x) -> sort (x));
  }
}