D.cpp

#include<bits/stdc++.h>
using namespace std;
#define fo(i,n) for(i=0;i<n;i++)
#define fo2(i,start,end) for(i=start;i<=end;i++)
#define rfo(i,n) for(i=n-1;i>=0;i--)
#define ll long long int
#define deb(x) cout<<#x<<"="<<x<<endl
#define deb2(x,y) cout<<#x<<"="<<x<<","<<#y<<"="<<y<<endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sortall(x) sort(all(x))
#define tr(it,a) for(auto it=a.begin(); it!=a.end();it++)
#define nl '\n'
#define PI 3.1415926535897932384626
#define mod 1000000007
typedef pair<int, int>	pii;
typedef pair<ll, ll>	pl;
typedef vector<int>		vi;
typedef vector<ll>		vl;
typedef vector<pii>		vpii;
typedef vector<pl>		vpl;
void solve(){
    int i,j;
    int n,temp;
    cin>>n;
    int pres[2*n+1]={0},l,r,ans;
    fo(i,n){
        cin>>temp;
        pres[temp]++;
    }
    vi a,b;
    fo2(i,1,2*n){
        if(pres[i]==1){
            a.pb(i);
        }
        else{
            b.pb(i);
        }
    }

    i=0;j=0;
    while(i<n && j<n){
        if(a[i]<b[j]){
            i++;
            j++;
        }
        else{
            j++;
        }
    }
    r=i;
    
    i=0;j=0;
    while(i<n && j<n){
        if(b[j]<a[i]){
            j++;
            i++;
        }
        else{
            i++;
        }
    }
    l=n-j;

    ans=r-l+1;
    cout<<ans<<nl;
}

int main(){
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t=1;
    cin>>t;
    while(t--){
        solve();
    }
}