static int[] moveZerosToEnd(int[] arr) {
    if(arr == null || arr.length ==0){
      return arr;
    }
		// your code goes here
    int zero = 0;
    int nonZero =0;
    while(zero<arr.length){
      while(zero<arr.length && arr[zero]!=0){
        zero++;
      }
      if(zero == arr.length){
        break;
      }
      nonZero = zero;
      while(nonZero<arr.length && arr[nonZero]==0){
          nonZero++;
      }

      if(nonZero == arr.length){
        break;
      }

      arr[zero] = arr[nonZero];
      arr[nonZero] = 0;
      zero = zero + 1;
    }
    return arr;

	}