카타 7급 Looking for a benefactor

2 R

newAvg <- function(arr, newavg){
  ret <- ceiling( (length(arr)+1)*newavg - sum(arr) )
  if( ret < 0 ) stop("ValueError") else ret
}

newAvg <- function(arr, newavg){
  x <- newavg * (length(arr) + 1) - sum(arr)
  if(x <= 0) stop("ValueError")
  ceiling(x)
}