Added new class to generate random numbers

src/com/jwetherell/algorithms/numbers/RandomNumbers.java

@@ -0,0 +1,49 @@
+import java.util.ArrayList;
+import java.util.Random;
+/**
+ * This class is used to generate n positive numbers randomly which sum upto a given positive value
+ * Currently negative sum is not supported
+ * @author Vaibhav Tripathi <tripathivaibhav140@gmail.com> 
+ * @version (a version number or a date)
+ */
+public class RandomNumbers
+{
+
+/**
+ * @param numberOfDraws 
+ * Number of random numbers needed
+ * @param targetSum
+ * The sum needed
+ * @return An arraylist which contains n numbers which sum upto the given value
+ */ 
+public ArrayList<Integer> n_random(int targetSum, int numberOfDraws) {
+ Random r = new Random();
+ ArrayList<Integer> load = new ArrayList<Integer>();
+
+ //random numbers
+ int sum = 0;
+ for (int i = 0; i < numberOfDraws; i++) {
+ int next = r.nextInt(targetSum) + 1;
+ load.add(next);
+ sum += next;
+ }
+
+ //scale to the desired target sum
+ double scale = 1d * targetSum / sum;
+ sum = 0;
+ for (int i = 0; i < numberOfDraws; i++) {
+ load.set(i, (int) (load.get(i) * scale));
+ sum += load.get(i);
+ }
+
+ //take rounding issues into account
+ while(sum++ < targetSum) {
+ int i = r.nextInt(numberOfDraws);
+ load.set(i, load.get(i) + 1);
+ }
+
+ //System.out.println("Random arraylist " + load);
+ //System.out.println("Sum is "+ (sum - 1));
+ return load;
+}
+}