
Answer:
The C++ code is explained below
Explanation:
#include<bits/stdc++.h>
using namespace std;
int main()
{
 vector<unsigned int>A;
 int n,i,num;
 cin>>n; // input no of elements
 for(i=0;i<n;i++)
 {
   cin>>num; // input elements
   A.push_back(num);
 }
 int hash[n+1]={0}; // Maintain a hash array.
 for(i=0;i<A.size();i++)
 {
   hash[A[i]]=1; //update hash array if element is present
 }
 cout<<"The missing elements are:-"<<endl;
 for(i=0;i<=n;i++)
 {
   if(hash[i]==0)
     cout<<i<<" ";
 }
}
Sample Input :-
5
3 3 3 4 5
Sample Output:-
The missing elements are:-
0 1 2 Â