004 Duplicate Zeros

Given a fixed length array arr of integers, duplicate each occurrence of zero, shifting the remaining elements to the right.

Note that elements beyond the length of the original array are not written.

Do the above modifications to the input array in place, do not return anything from your function.

Example 1:

Input: [1,0,2,3,0,4,5,0]
Output: null
Explanation: After calling your function, the input array is modified to: [1,0,0,2,3,0,0,4]

Example 2:

Input: [1,2,3]
Output: null
Explanation: After calling your function, the input array is modified to: [1,2,3]

Note:

1. 1 <= arr.length <= 10000

2. 0 <= arr[i] <= 9

Solution

C#

public class Solution {    
    public void DuplicateZeros(int[] arr) {
        bool dupicate = false;    
        //Traverse array from left to right to find 0;
        for(int count = 0; count<arr.Length; count++){
            if(arr[count]==0){                    //Find a zero
                if(dupicate == false){            //This zero is not a duplicate
                 //shift all the elements from that index onwards one position to the right. 
                 //Set the element beside that index to zero.
                 for(int index=arr.Length-1; index>count; index--){
                  arr[index] = arr[index-1];
                  arr[count] = 0;
                  dupicate = true;
                } 
            }
            count++;
            dupicate = false;     
          } 
        }        
    }  
}