USE C++

2 FILES: ONE header file (h) and one cpp File

7. Given an array of integers, 1s at sn (n = size of array), some elements appear twice and others appear once. Find all the elements that appear twice in this array. (10) Input (4,3,2782,3,1] Output: (2,3) Please implement your solution with given class: class Solution public: vector findDuplicates(vector