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  1. #include <bits/stdc++.h>
  2. #define int long long
  3. using namespace std;
  4.  
  5. void solve() {
  6.     int n;
  7.     cin >> n;
  8.     vector<int> v(n+1);
  9.     for(int i=1;i<=n;i++)cin>>v[i];
  10.     sort(v.begin(),v.end());
  11.     vector<int> a(n+1,0);
  12.     if(v[1]!=v[2]){
  13.     	cout<<"NO"<<endl;
  14.     	return;
  15.     }
  16.     a[v[1]]=1;
  17.     int k=v[1]+1;
  18.     for(int i=3;i<=n-1;i+=2){
  19.     	int p=v[i],q=v[i+1];
  20.     	if(p==q && a[p]==0){
  21.     		a[p]=1;
  22.     		continue;
  23.     	}
  24.     	else if(a[q-1]==1){
  25.     		p=q;
  26.     		a[p]=1;
  27.     	}
  28.     	else if(p==q){
  29.     		while(a[p]!=0 && p<=n){
  30.     			p++;
  31.     		}
  32.     		a[p]=1;
  33.     	}
  34.     	else{
  35.     		cout<<"NO"<<endl;
  36.     		return;
  37.     	}
  38.  
  39.     }
  40.     cout<<"YES"<<endl;
  41.  
  42. }
  43.  
  44. signed main() {
  45.     int t;
  46.     cin >> t;
  47.     while (t--) {
  48.         solve();
  49.     }
  50.     return 0;
  51. }
  52.  
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin
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9
2
1 1
2
2 1
4
1 1 4 4
4
3 4 3 3
4
2 3 4 4
6
3 3 4 5 3 3
6
2 2 2 4 4 4
8
1 1 1 1 1 1 1 4
10
9 9 9 10 10 10 10 10 10 10
stdout
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YES
NO
YES
YES
NO
YES
NO
YES
YES
https://ideone.com/Pxe5bQ
language:
C++ (gcc 8.3)
created:
10 days ago
visibility:
public

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