Distinguishing extra element from two arrays?

Question

One of my friend was asked this question in an interview -

• You have given two integer arrays each of size 10.
• Both contains 9 equal elements (say 1 t

Answer 1

Given two arrays say A1 of size 'n' and A2 of size 'n-1', both the arrays have same element except one which we have to find.

Note: elements in A1 can be repeated.

Example:

A1:{2,5,5,3}

A2:{2,5,3}

Output: 5

A1:{1,2,3,3,3}

A2:{2,3,1,3}

Output: 3

public static void main(String args[])
{
    int[] a ={1,2,3,3,3};
    int[] b ={2,3,1,3};
    int flag=1;
    int num=0;
    List lst = new ArrayList<>(b.length);
    for(int i : b)
        lst.add(Integer.valueOf(i));


    for(int i=0;i