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- #!/usr/bin/ruby
- #
- ## https://rosettacode.org/wiki/Bulls_and_cows/Player#Sidef
- #
- # Build a list of all possible solutions. The regular expression weeds
- # out numbers containing zeroes or repeated digits.
- var candidates = (1234..9876 -> grep {|n| !("#{n}" =~ /0 | (\d) .*? \1 /x) }.map{.digits});
- # Repeatedly prompt for input until the user supplies a reasonable score.
- # The regex validates the user's input and then returns two numbers.
- func read_score(guess) {
- loop {
- "My guess: %s (from %d possibilities)\n" \
- -> printf(guess.join, candidates.len);
- if (var m = (Sys.scanln("bulls cows: ") =~ /^\h*(\d)\h*(\d)\h*$/)) {
- var (bulls, cows) = m.cap.map{.to_i}...;
- bulls+cows <= 4 && return(bulls, cows);
- }
- say "Please specify the number of bulls and the number of cows";
- }
- }
- func score_correct(a, b, bulls, cows) {
- var (exact, loose) = (0, 0);
- for i in ^4 {
- a[i] == b[i] ? ++exact
- : (a[i]~~b && ++loose)
- }
- (bulls == exact) && (cows == loose)
- }
- # Pick a number, display it, get the score, and discard candidates
- # that don't match the score:
- loop {
- var guess = candidates.pick;
- var (bulls, cows) = read_score(guess);
- candidates.grep!{|n| score_correct(n, guess, bulls, cows) }
- candidates.len > 1 || break
- }
- # Print the secret number or the error message
- (
- candidates.len == 1 ? ("Your secret number is: %d" % candidates[0].join)
- : ("I think you made a mistake with your scoring")
- )->say
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