Question

How to sort an array of 0s, 1s and 2s in Java

Answer 1

public class MyClass {
    public static int swap(int... args) {
        return args[0];
    }
    
    private static void sort012Array(int[] arr) {
    	int lo = 0;
    	int curr = 0;
    	int hi = arr.length - 1;
    
    	while (curr <= hi) {
    		switch (arr[curr]) {
    			case 0:
    				arr[lo] = swap(arr[curr], arr[curr] = arr[lo]);
    				lo++;
    				curr++;
    				break;
    			case 1:
    				curr++;
    				break;
    			case 2:
    				arr[curr] = swap(arr[hi], arr[hi] = arr[curr]);
    				hi--;
    			    break;
    		}
    	}
    }
    
    public static void main(String args[]) {
        int[] arr = {1, 2, 2, 0, 1, 1, 0, 2, 0, 1, 0, 0, 1};

	    sort012Array(arr);

    	for (int i = 0; i < arr.length; i++) {
    		System.out.print(arr[i] + " ");
    	}
    }
}





/*
run:
 
0 0 0 0 0 1 1 1 1 1 2 2 2 
 
*/

 

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