DNFSort.java

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);
 }
}