Editorial

In this task, you must simulate the operations with the set. Let $x$ be the number thought of by Yuri. If $x$ is already present in the set, print "Yes" and the size of the set. Otherwise, add $x$ to the set, print "No", and the size of the set.

Algorithm realization

Declare a set $s$.

set<int> s;

Read the number of queries $n$.

scanf("%d",&n);

Process the $n$ queries sequentially.

for(i = 1; i <= n; i++)
{

Read the number $x$ that Yuri has thought of.

  scanf("%d",&x);

If the number $x$ is not in the set $s$, add it to the set, print "No", and the size of the set.

  if(s.find(x) == s.end())
  {
    s.insert(x);
    printf("No %d\n",s.size());
  }
  else

If the number $x$ is present in the set $s$, print "Yes" and the size of the set.

    printf("Yes %d\n",s.size());
}

Java realization

import java.util.*;
 
public class Main
{
  public static void main(String[] args)
  {
    Scanner con = new Scanner(System.in);
    TreeSet<Integer> s = new TreeSet<Integer>();
 
    int n = con.nextInt();
    for(int i = 0; i < n; i++)
    {
      int x = con.nextInt();
      if (s.contains(x))
        System.out.println("Yes " + s.size());
      else
      {
        s.add(x);
        System.out.println("No " + s.size());
      }
    }
    con.close();
  }
}   

Python realization

Read the number of queries $n$.

n = int(input())

Declare a set $s$.

s = set({})

Process the $n$ queries sequentially.

for _ in range(n):

Read the number $x$ that Yuri has thought of.

  x = int(input())

If the number $x$ is present in the set $s$, print "Yes" and the size of the set.

  if x in s:
    print("Yes", end = ' ')
  else:

If the number $x$ is not in the set $s$, add it to the set, print "No", and the size of the set.

    s.add(x)
    print("No", end = ' ')

After the message "Yes" or "No", print the size of the set.

  print(len(s))