Your task is to write a program, that given a list of chat messages, count how many times each person gets pinged, so I can know how popular everyone is. But, since I have to do it surreptitiously, I need it to be as small as possible so I can hide the code.


  • The input comes in a list of 2-tuples, with each item being of the form ("username", "message").
  • A ping to another user is defined as an @ followed by 3 or more letters that unambiguously refers to that user.
  • However, you also have to consider replies, which have to start with :messageid followed by a space.
  • Assume the first message has id 0 and proceed sequentially.
  • Output each user and say how many times each one got pinged.
  • The output can be in any order/reasonable format.
  • This is , so shortest code in bytes wins!

Test Cases

[["AlexA.", "I am wrong"], ["Quartatoes", "@Alex you are very wrong"], ["AlexA.", ":1 I am only slightly wrong"]]
AlexA.: 1
Quartatoes: 1

[["Doorknob", "I have never eaten an avocad."], ["AquaTart", ":0 I will ship you an avocad"], ["AlexA.", ":0 this is shocking"]]
Doorknob: 2
AquaTart: 0
AlexA.: 0

[["Geobits", "I like causing sadness through downvotes."], ["Flawr", "I want to put random message ids in my chat messages :0 askjdaskdj"]]
Geobits: 0
Flawr: 0

[["Downgoat", "goatigfs.com/goatgif"], ["Downotherthing", "@Downgoat cool gifs"], ["Dennis", "@Down cool gifs this is an ambiguous ping"]]
Downgoat: 1
Downotherthing: 0
Dennis: 0
  • 3
    \$\begingroup\$ I like how :0 doubles as a surprised emoticon. \$\endgroup\$
    – Doorknob
    Feb 29, 2016 at 14:08
  • 4
    \$\begingroup\$ "I like causing sadness through downvotes." You know there's only one proper way I can respond to that, right? ;) \$\endgroup\$
    – Geobits
    Feb 29, 2016 at 14:15
  • 9
    \$\begingroup\$ At what point are we stopping with the "Alex is wrong" jokes? \$\endgroup\$ Feb 29, 2016 at 15:36
  • 1
    \$\begingroup\$ Can a reply be out of range (e.g. first message starting with :3) or a ping not satisfying any user in the room (e.g. @zzz)? \$\endgroup\$
    – Sp3000
    Feb 29, 2016 at 16:33
  • 2
    \$\begingroup\$ Can a pinged user not yet have posted a message when he's pinged? e.g. is [["Doorknob","@Alex is wrong"],["Alex","I am only slightly wrong"]] valid input? \$\endgroup\$ Mar 1, 2016 at 1:19

2 Answers 2


JavaScript (ES6), 245 210 bytes


Uses an object to create a unique list of names alongside pings. Then it looks through the messages for matches to either ping condition. If a name, it looks through the list of names to find if there is only one match, and then increments. If a reply, it simply references that index in the message array and pulls the name to be incremented. Finally, it returns the object.

  • \$\begingroup\$ Surely using an object is shorter. If it isn't I don't think you need to return the Map as an array \$\endgroup\$
    – Downgoat
    Feb 29, 2016 at 22:56
  • \$\begingroup\$ @Downgoat But Map is more fun right? Na, I originally overestimated how much extra it would take to reference an object, thinking I would have to a separate array for names, but you're right that it is much shorter this way. \$\endgroup\$
    – Mwr247
    Mar 1, 2016 at 0:44

PHP, 227 Bytes

foreach($_GET[a]as $c){$r[]=&$n[$c[0]]??$n[$c[0]]=0;preg_match("#^(:(\d+)|@(\w+))#",$c[1],$m);$m[2]==""?!$m[3]?:count($a=preg_grep("#^{$m[3]}#",array_keys($n)))>1?:$n[end($a)]++:$r[$m[2]]++;}foreach(($n)as$k=>$v)echo"$k: $v\n";

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