From 2611ccfc354460945fcc1cbb5131d806ab2ba313 Mon Sep 17 00:00:00 2001
From: "marcins78@gmail.com"
 <marcins78@gmail.com@eb7970ca-0f6f-de4b-2938-835b230b9d1f>
Date: Thu, 10 Jan 2013 19:33:12 +0000
Subject: [PATCH] Added NumberUtils to generate combinations of numbers.

---
 .../lotro/tournament/NumberUtils.java         | 59 +++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 gemp-lotr/gemp-lotr-server/src/main/java/com/gempukku/lotro/tournament/NumberUtils.java

diff --git a/gemp-lotr/gemp-lotr-server/src/main/java/com/gempukku/lotro/tournament/NumberUtils.java b/gemp-lotr/gemp-lotr-server/src/main/java/com/gempukku/lotro/tournament/NumberUtils.java
new file mode 100644
index 000000000..a10dd2fd3
--- /dev/null
+++ b/gemp-lotr/gemp-lotr-server/src/main/java/com/gempukku/lotro/tournament/NumberUtils.java
@@ -0,0 +1,59 @@
+package com.gempukku.lotro.tournament;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class NumberUtils {
+    /**
+     * Chooses a combination of count numbers from 0<=i<maxNumber, without repetitions. This method will return different
+     * result for every "iteration" value (iteration starts at 0). If there is no more possible combinations, it will
+     * return null
+     *
+     * @param count
+     * @param maxNumber
+     * @param iteration
+     * @return
+     */
+    public static int[] selectOrderedCombinationOfNumbers(int count, int maxNumber, int iteration) {
+        if (count > maxNumber)
+            throw new IllegalArgumentException("Count cannot be bigger than maxNumber");
+
+        int left = iteration;
+        int[] indexes = new int[count];
+        for (int i = 0; i < count; i++) {
+            int resultWithOffset = left % (maxNumber - i);
+            indexes[i] = resultWithOffset;
+            left = left / (maxNumber - i);
+        }
+        if (left>0)
+            return null;
+        else {
+            List<Integer> values = new ArrayList<Integer>(maxNumber);
+            for (int i=0; i<maxNumber; i++)
+                values.add(i);
+
+            int[] result = new int[count];
+            for (int i=0; i<count; i++)
+                result[count-i-1] = values.remove(indexes[i]);
+
+            return result;
+        }
+    }
+
+    public static void main(String[] args) {
+        int count = 3;
+        int maxNumber = 5;
+        
+        int iteration = 0;
+        while (true) {
+            int[] result = selectOrderedCombinationOfNumbers(count, maxNumber, iteration);
+            if (result == null) {
+                System.out.println("Combinations: "+iteration);
+                break;
+            }
+            System.out.println(Arrays.toString(result));
+            iteration++;
+        }
+    }
+}