time_to_next_event.R

#
# time to next event
#

test.vectors <- list(
  list(
    input = c(1,0,0,0,2,3,4,0,0,0),
    output = c(4,3,2,1,1,1,Inf, Inf, Inf, Inf)
  ),
  list(
    input = c(1,0,0,0,2,3,0,0,4,0,0,0),
    output = c(4,3,2,1,1,3,2,1,Inf, Inf, Inf, Inf)
  )
)

time_to_next_event <- function (x) {
  state <- list(
    output = c(),
    counter = 1
  )
  
  lapply(tail(x, -1), function (a) {
    if (a == 0) {
      state$counter <<- state$counter + 1
    } else {
      state$output <<- list(state$output, state$counter:1)
      state$counter <<- 1
    }
  })
  
  state$output <- unlist(state$output)
  unlist(list(state$output, rep(Inf, length(x) - length(state$output))))
}

run_tests <- function(fn, cases) {
  for (case in cases) {
    actual.output <- fn(case$input)
    strs = list(
      actual = paste(actual.output, collapse = ','),
      expected = paste(case$output, collapse = ','),
      input = paste(case$input, collapse = ',')
    )
    if (all(actual.output == case$output)) {
      print(paste("OK! input:", strs$input, "expected:", strs$expected, "actual:", strs$actual))
    } else {
      print(paste("WRONG! input:", strs$input, "expected:", strs$expected, "actual:", strs$actual))
    }
  }
}