import java.util.*;
/***********************************************************
* Oblig 3 - sekvensiell kode, INF2440 v2016.
*            Ifi, Uio, Arne Maus
************************************************************/
class MultiRadix{
	int n;
	int [] a;
	final static int NUM_BIT =7; // alle tall 6-11 OK

	public static void main(String [] args) {
		if (args.length != 1) {
	     	System.out.println(" bruk : >java SekvensiellRadix <n> ");
		} else {
			int n = Integer.parseInt(args[0]);
			new MultiRadix().doIt(n);
		}
	} // end main

	void doIt (int len) {
		a = new int[len];
		Random r = new Random(123);
		for (int i =0; i < len;i++) {
		   a[i] = r.nextInt(len);
	    }
	    a = radixMulti(a);
	} // end doIt

    int []  radixMulti(int [] a) {
		  long tt = System.nanoTime();
		  // 1-5 digit radixSort of : a[]
		  int max = a[0], numBit = 2, numDigits, n =a.length;
		  int [] bit ;

		 // a) finn max verdi i a[]
		  for (int i = 1 ; i < n ; i++)
			   if (a[i] > max) max = a[i];
		  while (max >= (1L<<numBit) )numBit++; // antall siffer i max

		  // bestem antall bit i numBits sifre
		  numDigits = Math.max(1, numBit/NUM_BIT);
		  bit = new int[numDigits];
		  int rest = (numBit%numDigits), sum =0;;

		  // fordel bitene vi skal sortere paa jevnt
		  for (int i = 0; i < bit.length; i++){
			  bit[i] = numBit/numDigits;
		      if ( rest-- > 0)  bit[i]++;
		  }

		  int[] t=a, b = new int [n];

		  for (int i =0; i < bit.length; i++) {
			  radixSort( a,b,bit[i],sum );    // i-te siffer fra a[] til b[]
			  sum += bit[i];
			  // swap arrays (pointers only)
			  t = a;
			  a = b;
			  b = t;
		  }
		  if (bit.length%2 != 0 ) {
			  // et odde antall sifre, kopier innhold tilbake til original a[] (n? b)
			  System.arraycopy (a,0,b,0,a.length);
		  }

		  double tid = (System.nanoTime() -tt)/1000000.0;
		  System.out.println("\nSorterte "+n+" tall paa:" + tid + "millisek.");
		  testSort(a);
		  return a;
	 } // end radixMulti

	/** Sort a[] on one digit ; number of bits = maskLen, shiftet up 'shift' bits */
	 void radixSort ( int [] a, int [] b, int maskLen, int shift){
          System.out.println(" radixSort maskLen:"+maskLen+", shift :"+shift);
		  int  acumVal = 0, j, n = a.length;
		  int mask = (1<<maskLen) -1;
		  int [] count = new int [mask+1];

		 // b) count=the frequency of each radix value in a
		  for (int i = 0; i < n; i++) {
			 count[(a[i]>>> shift) & mask]++;
		  }

		 // c) Add up in 'count' - accumulated values
		  for (int i = 0; i <= mask; i++) {
			   j = count[i];
				count[i] = acumVal;
				acumVal += j;
		   }
		 // d) move numbers in sorted order a to b
		  for (int i = 0; i < n; i++) {
			 b[count[(a[i]>>>shift) & mask]++] = a[i];
		  }

	}// end radixSort

	void testSort(int [] a){
		for (int i = 0; i< a.length-1;i++) {
		   if (a[i] > a[i+1]){
		      System.out.println("SorteringsFEIL p? plass: "+i +" a["+i+"]:"+a[i]+" > a["+(i+1)+"]:"+a[i+1]);
		      return;
		  }
	  }
	 }// end simple sorteingstest
}// end SekvensiellRadix