sort012.java

// Java implementation of the approach
import java.io.*;

class sort012 {
	// Utility function to print the contents of an array
	static void printArr(int arr[], int n)
	{
		for (int i = 0; i < n; i++)
			System.out.print(arr[i] + " ");
	}

	// Function to sort the array of 0s, 1s and 2s
	static void sortArr(int arr[], int n)
	{
		int i, cnt0 = 0, cnt1 = 0, cnt2 = 0;

		// Count the number of 0s, 1s and 2s in the array
		for (i = 0; i < n; i++) {
			switch (arr[i]) {
			case 0:
				cnt0++;
				break;
			case 1:
				cnt1++;
				break;
			case 2:
				cnt2++;
				break;
			}
		}

		// Update the array
		i = 0;

		// Store all the 0s in the beginning
		while (cnt0 > 0) {
			arr[i++] = 0;
			cnt0--;
		}

		// Then all the 1s
		while (cnt1 > 0) {
			arr[i++] = 1;
			cnt1--;
		}

		// Finally all the 2s
		while (cnt2 > 0) {
			arr[i++] = 2;
			cnt2--;
		}

		// Print the sorted array
		printArr(arr, n);
	}

	// Driver code
	public static void main(String[] args)
	{
		int arr[] = { 2,2,2,2,0,0,1,0};
		int n = arr.length;
		sortArr(arr, n);
	}
}

// This code is contributed by shubhamsingh10