There are two sorted arrays. First one is of size m+n containing only m elements. Another one is of size n and contains n elements. Merge these two arrays into the first array of size m+n such that the output is sorted

MergeAnArrayOfSizeNIntoAnotherArrayOfSizeMPlusN.java

public class MergeAnArrayOfSizeNIntoAnotherArrayOfSizeMPlusN {
	
	static int NA=-1;
	
	//move m elements to end of array
	public static int[] moveToEnd(int[] mPlusN){
		
		int size = mPlusN.length;
		int i = size-1;
		int j = size-1;
		
		for(i = size-1; i>=0;i--){
			
			if(mPlusN[i] !=NA){
				mPlusN[j]=mPlusN[i];
				j--;
			}
			
			
		}
		return mPlusN;
		
	}
	
	//merge arrays from n element from mplusN to its end and from
	//0 index of n[] to its end
	public static void merge(int[] mPlusN, int[] N, int mPlusNcount, int nCount){
		
		int k=0;
		int i=nCount;
		int j=0;
		
		while(k<mPlusNcount){
			if(i<mPlusNcount && (mPlusN[i] <= N[j]) || (j==nCount)){
					mPlusN[k]=mPlusN[i];
					k++;
					i++;
				}
				else{
					mPlusN[k]=N[j];
					j++;
					k++;
					
				}
		}
	}
	
	public static void printArray(int arr[], int size)
	{
		  int i;
		  for (i=0; i < size; i++)
		    System.out.print(arr[i] + " ");
		 
		  System.out.print("\n");
		}
	
	public static void main(String[]args){
		 int mPlusN[] = {2, 8, NA, NA, NA, 13, NA, 15, 20};
		  int N[] = {5, 7, 9, 25};
		  int n = N.length;
		  int m =mPlusN.length;
		 
		  /*Move the m elements at the end of mPlusN*/
		  moveToEnd(mPlusN);
		 
		  /*Merge N[] into mPlusN[] */
		  merge(mPlusN, N, m, n);
		 
		  /* Print the resultant mPlusN */
		  printArray(mPlusN, m);
	}

}