Merge pull request #125 from roitt/integer-difference

Integer difference solution JAVA.

Author: blakeembrey

solutions/java/IntegerDifference.java

@@ -0,0 +1,28 @@
+import java.util.HashMap;
+
+public class IntegerDifference {
+	public static void main(String[] args) {
+		IntegerDifference id = new IntegerDifference();
+		int[] input = { 1, 1, 3, 3 };
+		int diff = 2;
+		System.out.print(id.getNumberOfElements(input, diff));
+	}
+
+	public int getNumberOfElements(int[] input, int diff) {
+		int numberOfElements = 0;
+		HashMap<Integer, Integer> sums = new HashMap<Integer, Integer>();
+		for (int i = 0; i < input.length; i++) {
+			int sum = diff + input[i];
+			if (sums.containsKey(sum))
+				sums.put(sum, sums.get(sum) + 1);
+			else
+				sums.put(sum, 1);
+		}
+		for (int i = 0; i < input.length; i++) {
+			if (sums.containsKey(input[i])) {
+				numberOfElements += sums.get(input[i]);
+			}
+		}
+		return numberOfElements;
+	}
+}