Which values ​​have the same hash?

Question

Information Security

What numbers have the same hash?
I’m solving the IS Olympiad and I don’t rummage for the hash, the code is given:

function firstGame(){
  if (isset($_GET['game1_green']) and isset($_GET['game1_red'])){
      if ($_GET['game1_green'] == $_GET['game1_red'])
        echo "Not so easy!";
      else if (sha1($_GET['game1_green']) === sha1($_GET['game1_red'])){
        echo "Good job! You've past the first game! <br>";
        return;
      }
  }
  die();
}

in line:

else if (sha1($_GET['game1_green']) === sha1($_GET['game1_red'])){

As I understand it, values ​​with the same hash are needed, but the values ​​should not be the same.

Answer 1

You need to find the SHA1 collision. Or use a collision that someone already found: https://shattered.it/static/shattered.pdf

Answer 2

what numbers have the same hash?

Well, it's your job to find them. Have you tried to do anything, or do you just want it done for you?
Then freelance for you.