Merge pull request #483 from Anadee11/MergeSt

Merge-Sort

Author: geekquad

java/sorting/merge-sort.java

@@ -0,0 +1,74 @@
+
+class MergeSort
+{
+
+void merge(int arr[], int l, int m, int r)
+{
+
+int n1 = m - l + 1;
+int n2 = r - m;
+
+
+int L[] = new int[n1];
+int R[] = new int[n2];
+
+
+for (int i = 0; i < n1; ++i)
+L[i] = arr[l + i];
+for (int j = 0; j < n2; ++j)
+R[j] = arr[m + 1 + j];
+int i = 0, j = 0;
+int k = l;
+while (i < n1 && j < n2) {
+if (L[i] <= R[j]) {
+arr[k] = L[i];
+i++;
+}
+else {
+arr[k] = R[j];
+j++;
+}
+k++;
+}
+while (i < n1) {
+arr[k] = L[i];
+i++;
+k++;
+}
+while (j < n2) {
+arr[k] = R[j];
+j++;
+k++;
+}
+}
+void sort(int arr[], int l, int r)
+{
+if (l < r) {
+int m =l+ (r-l)/2;
+sort(arr, l, m);
+sort(arr, m + 1, r);
+merge(arr, l, m, r);
+}
+}
+static void printArray(int arr[])
+{
+int n = arr.length;
+for (int i = 0; i < n; ++i)
+System.out.print(arr[i] + " ");
+System.out.println();
+}
+public static void main(String args[])
+{
+int arr[] = { 12, 11, 13, 5, 6, 7 };
+
+System.out.println("Given Array");
+printArray(arr);
+
+MergeSort ob = new MergeSort();
+ob.sort(arr, 0, arr.length - 1);
+
+System.out.println("\nSorted array");
+printArray(arr);
+}
+}
+