// Scott R. Shannon.  13th October 2019.  Java code to produce the sequence A328342

import java.util.ArrayList;
import java.util.HashMap;

public class A328342 {
	
	static ArrayList<Integer> sequence = new ArrayList<>();
	
	static int TOTVALS = 200;
	
	static HashMap<Integer,ArrayList<Integer>> saveIndex = new HashMap<>();

	static int lastVal, nextVal;	
	static int maxVal=0,minVal=0;
			
	public static void main(String[] argv) {
		
		sequence.add(0);
		sequence.add(0);
		sequence.add(1);
		sequence.add(0);
		sequence.add(1);
		sequence.add(2);
		lastVal = sequence.get(sequence.size()-1);
		
		ArrayList<Integer> zeroValues = new ArrayList<>();
		zeroValues.add(1); zeroValues.add(3);
		saveIndex.put(0, zeroValues);
		
		ArrayList<Integer> oneValues = new ArrayList<>();
		oneValues.add(2); oneValues.add(4);
		saveIndex.put(1, oneValues);

		for (int i=0;i<sequence.size();++i)
			System.out.print(sequence.get(i)+", ");
		
		for (int i=sequence.size()-1;i<TOTVALS;++i) {
					
			if (i%50000==0) System.out.println(i+"   "+maxVal+" "+minVal);
			
			if (saveIndex.containsKey(lastVal)) {
				ArrayList<Integer> indexes = saveIndex.get(lastVal);
				if (indexes.size()==2) {
					nextVal = (i - indexes.get(1)) - (indexes.get(1) - indexes.get(0));
					indexes.remove(0);
					indexes.add(i);
					saveIndex.put(lastVal,indexes);
				}
				else if (indexes.size()==1) {
					nextVal = i - indexes.get(0);
					indexes.add(i);
					saveIndex.put(lastVal,indexes);
				}
				else throw new RuntimeException("We should not get here 1!");
			}
			else {
				ArrayList<Integer> newVal = new ArrayList<>();
				newVal.add(i);
				saveIndex.put(lastVal,newVal);
				nextVal = 0;
			}

			sequence.add(nextVal);
			if (nextVal>maxVal) maxVal = nextVal;
			if (nextVal<minVal) minVal = nextVal;
					
			System.out.print(nextVal+", ");
			if (i%20==0) System.out.println();
			
			lastVal = nextVal;
			
		}
		
		System.out.println("\n\nMax value: "+maxVal+"   Min value: "+minVal+"\n");

		for (int i=0;i<maxVal;++i)
			if (!saveIndex.containsKey(i)) { System.out.println("Max + not present: "+i); break; }
		for (int i=0;i>=minVal;--i)
			if (!saveIndex.containsKey(i)) { System.out.println("Max - not present: "+i); break; }

	}
	

}