MergeSortedArray.java

class MergeSortedArray {
    /*
        Runtime: 0 ms, faster than 100.00% of Java online submissions for Merge Sorted Array.
        Memory Usage: 39.4 MB, less than 23.26% of Java online submissions for Merge Sorted Array.
    */
    
    
    public void merge(int[] A, int m, int[] B, int n) {
        // In this code we start comparison from the last index
        //first compare the last non-zero element of A with last element of B 
        
        while(m > 0 && n > 0){ //We need to make sure that both m and n should be initialized first
            if(A[m-1]>B[n-1]) // comparing elements
            {
                A[m+n-1]=A[m-1]; //last element set
                m--; //if the element is set from first array then decrease the m index
            }
            else
            {
                A[m+n-1]=B[n-1]; //last element set
                n--; //if the element is set from second array then decrease the n index
            }
        }
        // Special case where you dont have any initialize element in A and 1 elements in B then copy element of B in A
        while(n>0)
            {
                A[m+n-1]=B[n-1];
                n--;
            }

    }
}