import java.util.Arrays;

public class DuplicateZeros {

public void duplicateZeros(int[] arr) {

if(arr == null || arr.length == 0) return;

int pos = 0, len = 0;

for(int i = 0; i < arr.length; i++){

if(arr[i] == 0) len += 2;

else len++;

pos = i;

if(len >= arr.length) break;

}

int index = arr.length - 1;

if(len > arr.length){

arr[index--] = 0; pos--;

}

for(int i = pos; i >= 0; i--){

if(arr[i] == 0){

arr[index--] = 0;

arr[index--] = 0;

}else{

arr[index--] = arr[i];

}

}

}

public static void main(String[] args) {

DuplicateZeros duplicateZeros = new DuplicateZeros();

int[] arr = new int[]{1,0,2,3,0,4,5,0};

duplicateZeros.duplicateZeros(arr);

System.out.println(Arrays.toString(arr));

arr = new int[]{1,2,3};

duplicateZeros.duplicateZeros(arr);

System.out.println(Arrays.toString(arr));

arr = new int[]{1,1,0};

duplicateZeros.duplicateZeros(arr);

System.out.println(Arrays.toString(arr));

}

}