Bulls and cows/Player: Difference between revisions
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→{{header|R}}: Improved syntax.
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=={{header|R}}==
As we are picking our guesses randomly from the remaining valid guesses, it is likely that this solution is neither optimal, efficient, or particularly smart. However, it is much shorter than some of the other solutions, is reasonably idiomatic R, and does not break in any way that I know of. I am aware that there exists an optimal method of playing this game, but I neither know the algorithm nor was required by the task to implement it. For comparison, it would be interesting to see the optimal method submitted here as an alternative solution.
<lang rsplus>bullsAndCowsPlayer <- function()
{
guesses <- 1234:9876
#The next line is terrible code, but it's the most R way to convert a set of 4-digit numbers to their 4 digits.
guessDigits <- t(sapply(strsplit(as.character(guesses), ""), as.integer))
validGuesses <- guessDigits[apply(guessDigits, 1, function(x) length(unique(x)) == 4 && all(x != 0)), ]
repeat
{
remainingCasesCount <- length(validGuesses[, 1])
cat("Possibilities remaining:", remainingCasesCount)#Not required, but excellent when debugging.
guess <- validGuesses[sample(remainingCasesCount, 1), ]
guessAsOneNumber <- as.integer(paste(guess, collapse = ""))
bulls <- as.integer(readline(paste0("My guess is ", guessAsOneNumber, ". Bull score? [0-4] ")))
if(bulls == 4)
cows <- as.integer(readline("Cow score? [0-4] "))
pseudoBulls <- function(x)
#If our guess scores y bulls, then only numbers containing exactly y digits with the same value and position (y "pseudoBulls") as in our guess can be correct.
#Accounting for the positions of cows not being fixed, the same argument also applies for them.
#The
#We also use pseudoBulls != 4 to remove our most recent guess, because we know that it cannot be correct.
#Finally, the drop=FALSE flag is needed to stop R converting validGuesses to a vector when there is only one guess left.
validGuesses <- validGuesses[apply(validGuesses, 1, isGuessValid), , drop = FALSE]
if(length(validGuesses) == 0)
}
}
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