C.cpp

#include<bits/stdc++.h>
#include<string>
using namespace std;
#define fastio ios_base::sync_with_stdio(false);cin.tie(NULL)

long long ara[200005],b[200005];

int main()
{
    fastio;
    long long t,n,i,mex,gr,f,gs,s;
    cin>>t;
    while(t--)
    {
        cin>>n;
        s=0;
        map<long long,long long> mp;
        for(i=0;i<n;i++)
        {
            cin>>ara[i];
            b[i]=ara[i];
            mp[ara[i]]++;
        }
        sort(b,b+n);
        if(b[0]>0)
        {
            mex=0;
            gr=n;
            s=1;
        }
        else
        {
            for(i=1;i<n;i++)
            {
                if(b[i]>b[i-1]+1)
                {
                    mex=b[i-1]+1;
                    gr=n-i+1;
                    s=1;
                    break;
                }
            }
        }
        if(s==0)
        {
            mex=b[n-1]+1;
            gr=0;
        }
        if(n==1 && ara[0]==0)
        {
            cout<<"NO\n";
            continue;
        }
        if(mp[mex+1]==1)
        {
            cout<<"YES\n";
            continue;
        }
        if(mp[mex+1]==0)
        {
            if(b[n-1]>mex+1)
            {
                cout<<"YES\n";
                continue;
            }
            s=0;
            for(i=0;i<n;i++)
            {
                if(mp[b[i]]>1)
                {
                    s=1;
                    break;
                }
            }
            if(s==1)
            {
                cout<<"YES\n";
                continue;
            }
            else
            {
                cout<<"NO\n";
                continue;
            }
        }
        gs=-1;
        f=0;
        for(i=0;i<n;i++)
        {
            if(ara[i]==mex+1)
            {
                if(gs==-1)
                {
                    gs=0;
                }
                mp[mex+1]--;
                if(mp[mex+1]==0)
                    break;
            }
            else if(ara[i]>mex+1)
            {
                continue;
            }
            else
            {
                if(gs==0)
                {
                    if(mp[mex+1]>0)
                    {
                        if(mp[ara[i]]>1)
                            mp[ara[i]]--;
                        else
                        {
                            f=1;
                            break;
                        }
                    }
                }
            }
        }
        if(f==1)
            cout<<"NO\n";
        else
            cout<<"YES\n";
    }
    return 0;
}