Let's play Russian Roulette!

Normally, this would be a race to write the shortest MOD 6 program, but that's not very realistic, as the chance of winning decreases with each click. Here are the rules:

  1. Emulate a real six-shooter:
    • A single bullet is placed into one of the six chambers, and the barrel is spun once, only before playing.
    • The chance of losing on the nth try is 1/6.
    • The chance of losing after n tries is 1/(6-n)
    • You are guaranteed to lose in, at most, 6 tries.
  2. Losing:
    • Display the text *BANG!*
    • Terminate the program.
  3. Winning:
    • "Winning" means the gun does not fire, but the bullet is one chamber closer to the hammer.
    • Display the text *click*
    • Present a "trigger" to the user, along with the ability to terminate the program (e.g. "ctrl+c", see below).
  4. Program specific:
    • Pulling the trigger is some form of user input, including the first try. (This can be a keystroke, a mouse click, whatever; text prompts are not required.)
    • Only one instance of the program is allowed until it is terminated. (Running a new instance of the program is akin to giving the barrel a good spin, i.e. the probability of losing on the next click is reset to 1/6.)

Shortest code wins!


<style>body { text-align: left !important} #answer-list { padding: 10px; width: 290px; float: left; } #language-list { padding: 10px; width: 290px; float: left; } table thead { font-weight: bold; } table td { padding: 5px; }</style><script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <link rel="stylesheet" type="text/css" href="//cdn.sstatic.net/codegolf/all.css?v=83c949450c8b"> <div id="language-list"> <h2>Shortest Solution by Language</h2> <table class="language-list"> <thead> <tr><td>Language</td><td>User</td><td>Score</td></tr> </thead> <tbody id="languages"> </tbody> </table> </div> <div id="answer-list"> <h2>Leaderboard</h2> <table class="answer-list"> <thead> <tr><td></td><td>Author</td><td>Language</td><td>Size</td></tr> </thead> <tbody id="answers"> </tbody> </table> </div> <table style="display: none"> <tbody id="answer-template"> <tr><td>{{PLACE}}</td><td>{{NAME}}</td><td>{{LANGUAGE}}</td><td>{{SIZE}}</td><td><a href="{{LINK}}">Link</a></td></tr> </tbody> </table> <table style="display: none"> <tbody id="language-template"> <tr><td>{{LANGUAGE}}</td><td>{{NAME}}</td><td>{{SIZE}}</td><td><a href="{{LINK}}">Link</a></td></tr> </tbody> </table><script>var QUESTION_ID = 66763; var ANSWER_FILTER = "!t)IWYnsLAZle2tQ3KqrVveCRJfxcRLe"; var COMMENT_FILTER = "!)Q2B_A2kjfAiU78X(md6BoYk"; var OVERRIDE_USER = 38512; var answers = [], answers_hash, answer_ids, answer_page = 1, more_answers = true, comment_page; function answersUrl(index) { return "https://api.stackexchange.com/2.2/questions/" + QUESTION_ID + "/answers?page=" + index + "&pagesize=100&order=desc&sort=creation&site=codegolf&filter=" + ANSWER_FILTER; } function commentUrl(index, answers) { return "https://api.stackexchange.com/2.2/answers/" + answers.join(';') + "/comments?page=" + index + "&pagesize=100&order=desc&sort=creation&site=codegolf&filter=" + COMMENT_FILTER; } function getAnswers() { jQuery.ajax({ url: answersUrl(answer_page++), method: "get", dataType: "jsonp", crossDomain: true, success: function (data) { answers.push.apply(answers, data.items); answers_hash = []; answer_ids = []; data.items.forEach(function(a) { a.comments = []; var id = +a.share_link.match(/\d+/); answer_ids.push(id); answers_hash[id] = a; }); if (!data.has_more) more_answers = false; comment_page = 1; getComments(); } }); } function getComments() { jQuery.ajax({ url: commentUrl(comment_page++, answer_ids), method: "get", dataType: "jsonp", crossDomain: true, success: function (data) { data.items.forEach(function(c) { if (c.owner.user_id === OVERRIDE_USER) answers_hash[c.post_id].comments.push(c); }); if (data.has_more) getComments(); else if (more_answers) getAnswers(); else process(); } }); } getAnswers(); var SCORE_REG = /<h\d>\s*([^\n,<]*(?:<(?:[^\n>]*>[^\n<]*<\/[^\n>]*>)[^\n,<]*)*),.*?(\d+)(?=[^\n\d<>]*(?:<(?:s>[^\n<>]*<\/s>|[^\n<>]+>)[^\n\d<>]*)*<\/h\d>)/; var OVERRIDE_REG = /^Override\s*header:\s*/i; function getAuthorName(a) { return a.owner.display_name; } function process() { var valid = []; answers.forEach(function(a) { var body = a.body; a.comments.forEach(function(c) { if(OVERRIDE_REG.test(c.body)) body = '<h1>' + c.body.replace(OVERRIDE_REG, '') + '</h1>'; }); var match = body.match(SCORE_REG); if (match) valid.push({ user: getAuthorName(a), size: +match[2], language: match[1], link: a.share_link, }); else console.log(body); }); valid.sort(function (a, b) { var aB = a.size, bB = b.size; return aB - bB }); var languages = {}; var place = 1; var lastSize = null; var lastPlace = 1; valid.forEach(function (a) { if (a.size != lastSize) lastPlace = place; lastSize = a.size; ++place; var answer = jQuery("#answer-template").html(); answer = answer.replace("{{PLACE}}", lastPlace + ".") .replace("{{NAME}}", a.user) .replace("{{LANGUAGE}}", a.language) .replace("{{SIZE}}", a.size) .replace("{{LINK}}", a.link); answer = jQuery(answer); jQuery("#answers").append(answer); var lang = a.language; lang = jQuery('<a>'+lang+'</a>').text(); languages[lang] = languages[lang] || {lang: a.language, lang_raw: lang.toLowerCase(), user: a.user, size: a.size, link: a.link}; }); var langs = []; for (var lang in languages) if (languages.hasOwnProperty(lang)) langs.push(languages[lang]); langs.sort(function (a, b) { if (a.lang_raw > b.lang_raw) return 1; if (a.lang_raw < b.lang_raw) return -1; return 0; }); for (var i = 0; i < langs.length; ++i) { var language = jQuery("#language-template").html(); var lang = langs[i]; language = language.replace("{{LANGUAGE}}", lang.lang) .replace("{{NAME}}", lang.user) .replace("{{SIZE}}", lang.size) .replace("{{LINK}}", lang.link); language = jQuery(language); jQuery("#languages").append(language); } }</script>

  • 3
    \$\begingroup\$ Your assumptions are wrong - the chance of losing on the n'th try is only ⅙ if you respin the bullets after each shot. Without respinning the chance of losing is ⅙ on the first shot, ⅕ on the second, ¼ on the third... ending in 1 on the 6th. You recognise this with "You are guaranteed to lose in, at most, 6 tries". \$\endgroup\$ – rhialto Dec 16 '15 at 21:52
  • 2
    \$\begingroup\$ @user2956063 you are forgetting that there is a (n-1)/6 chance that you never reach the n:th try, and thus cannot lose. They balance out to a uniform 1/6. \$\endgroup\$ – Jacob Raihle Dec 17 '15 at 10:26
  • 2
    \$\begingroup\$ maybe that's a difference in the way computer scientists and statisticians express probability then - to me "The chance of losing on the nth try is ⅙" say's it's constant - whether n is 1 or 100. \$\endgroup\$ – rhialto Dec 17 '15 at 11:53
  • 3
    \$\begingroup\$ Why was this not titled "Russian Roulette, Reloaded"? \$\endgroup\$ – Hand-E-Food Dec 18 '15 at 4:51
  • 1
    \$\begingroup\$ @user2956063: Your probabilities are conditional. P(lose on shot 2) = ⅙, but P(lose on shot 2 | didn't lose on shot 1) = ⅕. Also, n is (implicitly, I'll grant you) limited to [1,6], so 100 is out. \$\endgroup\$ – Tim Pederick Dec 19 '15 at 5:04

32 Answers 32


R, 79 bytes


readline();for(n in 6:1)ifelse(1/n>=runif(1),cat("*Bang*"),readline("*click*"))


readline()                    # Waits for user to press [Enter] if [Esc] is pressed exits    
for(n in 6:1) {               # for n=6 to n=1
  ifelse(1/n >= runif(1),     # if 1/n >= a random float from 0 to 1 (uniform dist)
     cat("*Bang*"),           # *You're dead*
     readline("*click*")    # else you have another chance, waits for [Enter] again

The program will wait for an [Enter] before every try, if the user press [Esc] instead the program will end. If the *Bang* happens the program will print it and throw an error, thus terminating itself (is this correct?).


C, 96 bytes (Without counting comment)

#define R 4//chosen by playing russian roulette, guaranteed to be random
int main(){for(;c++<R&&puts(c<R?"Fire?":"☠Bang!☠");getchar(),puts("*click*"));}

Formatted :

#define R 4 // chosen by playing russian roulette, guaranteed to be random
int main(int c) {
    for( ; c++ < R && puts(c < R ? "Fire?" : "☠Bang!☠") ; getchar(), puts("*click*") );

Explanation :

There also is a click when it fires, that's the sound of the hammer being released.

After the bang you need to hit enter to take the gun out of the dead man's hand, rigor mortis squeezed his finger around the trigger. While you are prying his hand open you hear another click as the trigger snaps back into normal position.


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