661A.cpp

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*/                              
#include<bits/stdc++.h>
using namespace std;
 
#define fastio ios_base::sync_with_stdio(0); cin.tie(0)
#define LL long long 
#define mod 1000000007 
#define all(v) v.begin(),v.end()
#define FOR(i, j, k) for (auto i=j ; i<k ; i++)
#define ROF(i, j, k) for (auto i=j ; i>=k ; i--) 
#define debug(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#define time__(d) for(long blockTime = 0; (blockTime == 0 ? (blockTime=clock()) != 0 : false); debug("%s time : %.4fs", d, (double)(clock() - blockTime) / CLOCKS_PER_SEC))

const long long INF = 1e18;
const long long MAX = 2e5+10;
bool prime[MAX]; 

void Si(){ 
    memset(prime, true, sizeof(prime));   
    for (int p=2; p*p<MAX; p++)     
        if (prime[p] == true)         
            for (int i=p*p; i<MAX; i += p) 
                    prime[i] = false; 
} 
int main(){
    fastio;
    int t=1; cin>>t;
    while(t--){
         int n; cin>>n; vector<int>a(n); FOR(i,0,n) cin>>a[i];
         sort(all(a));
         int i =1;
         while(i<n && abs(a[i]-a[i-1])<=1) i++;
         if(i==n) cout<<"YES\n";
         else cout<<"NO\n";
    }
}