19 lines
803 B
R
19 lines
803 B
R
mod1 = function(v, n)
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# mod1(1:20, 6) => 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2
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((v - 1) %% n) + 1
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str2ints = function(s)
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as.integer(Filter(Negate(is.na),
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factor(levels = LETTERS, strsplit(toupper(s), "")[[1]])))
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vigen = function(input, key, decrypt = F)
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{input = str2ints(input)
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key = rep(str2ints(key), len = length(input)) - 1
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paste(collapse = "", LETTERS[
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mod1(input + (if (decrypt) -1 else 1)*key, length(LETTERS))])}
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message(vigen("Beware the Jabberwock, my son! The jaws that bite, the claws that catch!", "vigenerecipher"))
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# WMCEEIKLGRPIFVMEUGXQPWQVIOIAVEYXUEKFKBTALVXTGAFXYEVKPAGY
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message(vigen("WMCEEIKLGRPIFVMEUGXQPWQVIOIAVEYXUEKFKBTALVXTGAFXYEVKPAGY", "vigenerecipher", decrypt = T))
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# BEWARETHEJABBERWOCKMYSONTHEJAWSTHATBITETHECLAWSTHATCATCH
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