Binary Search

題目連結

https://learn.cylabacademy.org/library/442

題目解法

使用 ssh 連線進去，不斷猜範圍內的鄭中間一定可以在 10 次內猜到。

webshell:~$ ssh -p 58451 ctf-player@atlas.picoctf.net
The authenticity of host '[atlas.picoctf.net]:58451 ([18.217.83.136]:58451)' can't be established.
ED25519 key fingerprint is SHA256:M8hXanE8l/Yzfs8iuxNsuFL4vCzCKEIlM/3hpO13tfQ.
This host key is known by the following other names/addresses:
    ~/.ssh/known_hosts:3: [hashed name]
    ~/.ssh/known_hosts:5: [hashed name]
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '[atlas.picoctf.net]:58451' (ED25519) to the list of known hosts.
ctf-player@atlas.picoctf.net's password: 
Welcome to the Binary Search Game!
I'm thinking of a number between 1 and 1000.
Enter your guess: 500
Lower! Try again.
Enter your guess: 250
Higher! Try again.
Enter your guess: 375
Higher! Try again.
Enter your guess: 438
Higher! Try again.
Enter your guess: 469
Higher! Try again.
Enter your guess: 485
Higher! Try again.
Enter your guess: 493
Higher! Try again.
Enter your guess: 497
Higher! Try again.
Enter your guess: 499
Congratulations! You guessed the correct number: 499
Here's your flag: picoCTF{g00-------------07f}
Connection to atlas.picoctf.net closed.