add MergeSort.java

Author: jdevfullstack

Diff for: src/MergeSort.java

@@ -0,0 +1,77 @@
+public class MergeSort {
+
+	public static int[] mergeTwoSortedArrays(int[] one, int[] two) {
+
+		int[] sorted = new int[one.length + two.length];
+
+		int i = 0;
+		int j = 0;
+		int k = 0;
+
+		while (i < one.length && j < two.length) {
+
+			if (one[i] < two[j]) {
+				sorted[k] = one[i];
+				k++;
+				i++;
+			} else {
+				sorted[k] = two[j];
+				k++;
+				j++;
+			}
+		}
+
+		if (i == one.length) {
+
+			while (j < two.length) {
+				sorted[k] = two[j];
+				k++;
+				j++;
+			}
+		}
+
+		if (j == two.length) {
+
+			while (i < one.length) {
+				sorted[k] = one[i];
+				k++;
+				i++;
+			}
+		}
+
+		return sorted;
+
+	}
+
+	public static int[] mergeSort(int[] arr, int lo, int hi) {
+
+		if (lo == hi) {
+			int[] br = new int[1];
+			br[0] = arr[lo];
+
+			return br;
+		}
+
+		int mid = (lo + hi) / 2;
+
+		int[] fh = mergeSort(arr, lo, mid);
+		int[] sh = mergeSort(arr, mid + 1, hi);
+
+		int[] merged = mergeTwoSortedArrays(fh, sh);
+
+		return merged;
+	}    
+
+	public static void main(String[] args) {
+
+		int[] arr = { 70, 50, 30, 10, 20, 40, 60 };
+
+		int[] merged = mergeSort(arr, 0, arr.length - 1);
+
+		for (int val : merged) {
+			System.out.print(val + " ");
+		}
+
+	}
+
+}