Problem A Subset Mex Editorial | Codeforces Round 670 Div 2

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[theiitiancoder]

* $Id$
* File:
*
* Purpose:
*
* Author: Sanchit Gupta (CS19B071)
*
* Created:
*
* Last modified:
*
* Bugs:
*
* Change Log:
*
* While(!(succeed==try());

#include<iostream>
#include<bits/stdc++.h>

using namespace std;

int main()
{
int t;
cin>>t;
while(t--)
{
int n;
cin>>n;
int arr[n];
int i=0;
while(i!=n)
{
cin>>arr[i];
i++;
}
int freq[101]={0};
i=0;
while(i!=n)
{
freq[arr[i]]++;
i++;
}
int ans=0;
int flag0=0, flag1=0;
i=0;
while(i!=101 && (flag0==0 || flag1==0))
{
if(freq[i]==0)
{
if(flag1==0)
{
ans=ans+i;
flag1=1;
}
if(flag0==0)
{
ans=ans+i;
flag0=1;
}
break;
}
else if(freq[i]==1 && flag1==0 && flag0==0)
{
if(flag1==0)
{
ans=ans+i;
flag1=1;
}
else if(flag0==0)
{
ans=ans+i;
flag0=1;
}
}
else
{

}
i++;
}
cout<<ans<<endl;
}
}