Add DNF sort (#2400)

Sorts/DNFSort.java

@@ -0,0 +1,49 @@
+package Sorts;
+
+public class DNFSort {
+    // Sort the input array, the array is assumed to
+    // have values in {0, 1, 2}
+    static void sort012(int a[], int arr_size) {
+        int low = 0;
+        int high = arr_size - 1;
+        int mid = 0, temp = 0;
+        while (mid <= high) {
+            switch (a[mid]) {
+                case 0: {
+                    temp = a[low];
+                    a[low] = a[mid];
+                    a[mid] = temp;
+                    low++;
+                    mid++;
+                    break;
+                }
+                case 1:
+                    mid++;
+                    break;
+                case 2: {
+                    temp = a[mid];
+                    a[mid] = a[high];
+                    a[high] = temp;
+                    high--;
+                    break;
+                }
+            }
+        }
+    }
+
+    /* Utility function to print array arr[] */
+    static void printArray(int arr[], int arr_size) {
+        for (int i = 0; i < arr_size; i++)
+            System.out.print(arr[i] + " ");
+        System.out.println("");
+    }
+
+    /*Driver function to check for above functions*/
+    public static void main(String[] args) {
+        int arr[] = { 0, 1, 1, 0, 1, 2, 1, 2, 0, 0, 0, 1 };
+        int arr_size = arr.length;
+        sort012(arr, arr_size);
+        System.out.println("Array after seggregation ");
+        printArray(arr, arr_size);
+    }
+}