Treasure Tree

Connecting to the netcat instance, we are greeted with the following:

└─# nc challs.sieberr.live 4000
1 2
2 12
3 13
5 9
6 7
7 13
10 9
9 0
0 8
11 8
13 4
4 14
14 8
8 12
12 15
Guess where the flag is hidden:

Drawing

Lets map out all the nodes of the trees on paper

Tree

Afterwards, we pick a node and start guessing

Guess where the flag is hidden: 8
The flag is in the direction of node 14
Guess where the flag is hidden: 13
The flag is in the direction of node 4
Guess where the flag is hidden: 14
The flag is in the direction of node 4
Guess where the flag is hidden: 4
sctf{tr33_gr4ph_th30ry_sp3c14l1st}

By following the tree like a map, we can get the flag

sctf{tr33_gr4ph_th30ry_sp3c14l1st}