Task: Stem-and-leaf plot
C#: using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static void Main()
    {
        const string data =
        "12 127 28 42 39 113 42 18 44 118 44 37 113 124 37 48 127 36 29 31 " +
        "125 139 131 115 105 132 104 123 35 113 122 42 117 119 58 109 23 " +
        "105 63 27 44 105 99 41 128 121 116 125 32 61 37 127 29 113 121 58 " +
        "114 126 53 114 96 25 109 7 31 141 46 13 27 43 117 116 27 7 68 40 31 " +
        "115 124 42 128 52 71 118 117 38 27 106 33 117 116 111 40 119 47 " +
        "105 57 122 109 124 115 43 120 43 27 27 18 28 48 125 107 114 34 " +
        "133 45 120 30 127 31 116 146";

        int[] ints = data.Split(' ').Select(int.Parse).ToArray();

        StemAndLeafPlot(ints);

        Console.ReadKey();
    }

    public static void StemAndLeafPlot(int[] arr)
    {
        int stemMax = arr.Max() / 10;
        int stemMin = arr.Min() / 10;
        Array.Sort(arr);

        for (int i = stemMin; i <= stemMax; i++)
        {
            Console.Write("{0,3} | ", i);
            foreach (var t in arr)
            {
                if (t < 10 * i)
                    continue;
                if (t >= 10 * (i + 1))
                    break;
                Console.Write("{0} ", t % 10);
            }
            Console.WriteLine("");
        }
    }
}

Java: import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

public class StemAndLeaf {
	private static int[] data = { 12, 127, 28, 42, 39, 113, 42, 18, 44, 118,
			44, 37, 113, 124, 37, 48, 127, 36, 29, 31, 125, 139, 131, 115, 105,
			132, 104, 123, 35, 113, 122, 42, 117, 119, 58, 109, 23, 105, 63,
			27, 44, 105, 99, 41, 128, 121, 116, 125, 32, 61, 37, 127, 29, 113,
			121, 58, 114, 126, 53, 114, 96, 25, 109, 7, 31, 141, 46, 13, 27,
			43, 117, 116, 27, 7, 68, 40, 31, 115, 124, 42, 128, 52, 71, 118,
			117, 38, 27, 106, 33, 117, 116, 111, 40, 119, 47, 105, 57, 122,
			109, 124, 115, 43, 120, 43, 27, 27, 18, 28, 48, 125, 107, 114, 34,
			133, 45, 120, 30, 127, 31, 116, 146 };
	
	public static Map<Integer, List<Integer>> createPlot(int... data){
		Map<Integer, List<Integer>> plot = new TreeMap<Integer, List<Integer>>();
		int highestStem = -1; 
		for(int datum:data){
			int leaf = datum % 10;
			int stem = datum / 10; 
			if(stem > highestStem){
				highestStem = stem;
			}
			if(plot.containsKey(stem)){
				plot.get(stem).add(leaf);
			}else{
				LinkedList<Integer> list = new LinkedList<Integer>();
				list.add(leaf);
				plot.put(stem, list);
			}
		}
		if(plot.keySet().size() < highestStem + 1  ){
			for(int i = 0; i <= highestStem; i++){
				if(!plot.containsKey(i)){
					LinkedList<Integer> list = new LinkedList<Integer>();
					plot.put(i, list);
				}
			}
		}
		return plot;
	}
	
	public static void printPlot(Map<Integer, List<Integer>> plot){
		for(Map.Entry<Integer, List<Integer>> line : plot.entrySet()){
			Collections.sort(line.getValue());
			System.out.println(line.getKey() + " | " + line.getValue());
		}
	}
	
	public static void main(String[] args){
		Map<Integer, List<Integer>> plot = createPlot(data);
		printPlot(plot);
	}
}