# roundUp(n, multiple)
# --------------------
# Rounds the integer n *up* to the nearest multiple of `multiple`.
#
# Mathematically:
# result = ceil(n / multiple) * multiple
#
# We use integer arithmetic for efficiency:
# (n + multiple - 1) / multiple → smallest integer ≥ n/m
def round_up(n, multiple)
if multiple <= 0
# Defensive programming: avoid undefined behavior.
# In real-world code, you'd throw or handle this differently.
return n
end
# Efficient integer rounding up:
((n + multiple - 1) / multiple) * multiple
end
# main
puts "roundUp(53, 20) = #{round_up(53, 20)}"
puts "roundUp(68, 30) = #{round_up(68, 30)}"
puts "roundUp(7, 100) = #{round_up(7, 100)}"
puts "roundUp(119, 100) = #{round_up(119, 100)}"
puts "roundUp(781, 100) = #{round_up(781, 100)}"
puts "roundUp(1026, 100) = #{round_up(1026, 100)}"
puts "roundUp(11689, 1000) = #{round_up(11689, 1000)}"
# run:
#
# roundUp(53, 20) = 60
# roundUp(68, 30) = 90
# roundUp(7, 100) = 100
# roundUp(119, 100) = 200
# roundUp(781, 100) = 800
# roundUp(1026, 100) = 1100
# roundUp(11689, 1000) = 12000
#
