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diff --git a/AlgoDesignAndTechniqueEdxJava/sources/InversionCount.java b/AlgoDesignAndTechniqueEdxJava/sources/InversionCount.java
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+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Scanner;
+import java.util.stream.Collectors;
+
+public class InversionCount {
+
+	public static void main(String[] args) {
+		Scanner scanner = new Scanner(System.in);
+		int n = scanner.nextInt();
+		int[] a = new int[n];
+		for (int i = 0; i < n; i++) {
+			a[i] = scanner.nextInt();
+		}
+//		int[] b = new int[n];
+		System.out.println(getInversionCountFromArray(a));
+		scanner.close();
+	}
+
+	public static long getNumberOfInversions(int[] a, int[] b, int left, int right) {
+		long numberOfInversions = 0;
+		if (right <= left + 1) {
+			return numberOfInversions;
+		}
+		int middle = (left + right) / 2;
+		numberOfInversions += getNumberOfInversions(a, b, left, middle);
+		numberOfInversions += getNumberOfInversions(a, b, middle, right);
+		// write your code here
+		return numberOfInversions;
+	}
+
+	public static long getInversionCountFromArray(int[] a) {
+		List<Integer> aList = Arrays.stream(a).boxed().collect(Collectors.toList());
+		List<Integer> D = new ArrayList<Integer>();
+		long numberOfInversions = getInversionCountFromList(aList, D);
+		return numberOfInversions;
+	}
+
+	private static long getInversionCountFromList(List<Integer> A, List<Integer> D) {
+		long numberOfInversions = 0;
+		if (A.size() == 1) {
+			D.add(A.get(0));
+			return 0;
+		}
+		int m = A.size() / 2;
+		List<Integer> D1 = new ArrayList<Integer>();
+		numberOfInversions += getInversionCountFromList(new ArrayList<Integer>(A.subList(0, m)), D1);
+		List<Integer> D2 = new ArrayList<Integer>();
+		numberOfInversions += getInversionCountFromList(new ArrayList<Integer>(A.subList(m, A.size())), D2);
+//		long mergeCount = mergeInversionCount(new ArrayList<Integer>(A.subList(0, m)), new ArrayList<Integer>(A.subList(m, A.size())));
+		long mergeCount = mergeInversionCount(D1, D2, D);
+		return numberOfInversions + mergeCount;
+	}
+
+	private static long mergeInversionCount(List<Integer> B, List<Integer> C, List<Integer> D) {
+		long count = 0;
+		while (B.size() != 0 && C.size() != 0) {
+			int b = B.get(0);
+			int c = C.get(0);
+			if (b <= c) {
+				D.add(b);
+				B.remove(0);
+			} else {
+				count += B.size();
+				D.add(c);
+				C.remove(0);
+			}
+		}
+		D.addAll(B);
+		D.addAll(C);
+		return count;
+	}
+
+	public static int[] mergeSortArray(int[] a) {
+		List<Integer> aList = Arrays.stream(a).boxed().collect(Collectors.toList());
+		List<Integer> sortedList = mergeSortList(aList);
+		return sortedList.stream().mapToInt(i -> i).toArray();
+	}
+
+	private static List<Integer> mergeSortList(List<Integer> A) {
+		if (A.size() == 1)
+			return A;
+		int m = A.size() / 2;
+		List<Integer> B = mergeSortList(new ArrayList<Integer>(A.subList(0, m)));
+		List<Integer> C = mergeSortList(new ArrayList<Integer>(A.subList(m, A.size())));
+		List<Integer> aPrime = mergeList(B, C);
+		return aPrime;
+	}
+
+	private static List<Integer> mergeList(List<Integer> B, List<Integer> C) {
+		List<Integer> D = new ArrayList<>();
+		while (B.size() != 0 && C.size() != 0) {
+			int b = B.get(0);
+			int c = C.get(0);
+			if (b <= c) {
+				D.add(b);
+				B.remove(0);
+			} else {
+				D.add(c);
+				C.remove(0);
+			}
+		}
+		D.addAll(B);
+		D.addAll(C);
+		return D;
+	}
+
+}