CodeIQ《ピッグデータ》に負けないで！ - https://codeiq.jp/ace/yuki_hiroshi/q303

pigdata.simple.R

library(digest)
# R's index starts with 1, not 0

getdata <- function(index) {
    q <- floor(index / 10)
    r <- index %% 10
    digest.raw <- digest(as.character(q), algo="sha1", serialize=FALSE, raw=TRUE)
    data <- sum(as.numeric(digest.raw)[c(2 * r + 1, 2 * r + 1 + 1)] * c(256, 1))
    return(data)
}

getsign <- function(count, skips) {
    data <- sapply(0:(count - 1), getdata)
    target <- seq(0, count - 1, by=skips)
    return(sum(data[order(data)][target + 1]))
}