카타 8급 Sum of Multiples

R

sum_mul <- function(n, m){
  if( n < 1 | m < 1 ) return("INVALID")
  if( n >= m ) return(0)
  sum(seq(from=n, to=(m-1), by=abs(n)))
}

sum_mul <- function(n, m){
  if( n < 1 | m < 1 ) return("INVALID")
  if( n >= m ) return(0)
  v <- c(n:(m-1))
  sum(v[v %% n == 0])
}

sum_mul <- function(n, m){
  if( n < 1 | m < 1 ) return("INVALID")
  t <- (m-1)%/%n
  n * t * (t+1) / 2
}

sum_mul <- function(n, m){
  if( n < 1 | m < 1 ) return("INVALID")
  x = n
  sum = 0
  while( x < m ) {
    sum = sum + x
    x = x + n
  }
  sum
}