28 lines
511 B
Ruby
28 lines
511 B
Ruby
|
# @param {Integer} n
|
||
|
|
# @return {Integer}
|
||
|
|
def climb_stairs(n)
|
||
|
|
possible_ways = [0, 1, 2]
|
||
|
|
|
||
|
|
k = 3
|
||
|
|
while possible_ways.size <= n do
|
||
|
|
possible_ways.push(possible_ways[k - 1] + possible_ways[k - 2])
|
||
|
|
k += 1
|
||
|
|
end
|
||
|
|
|
||
|
|
return possible_ways[n]
|
||
|
|
end
|
||
|
|
|
||
|
|
RSpec.describe "climb_stairs" do
|
||
|
|
it "1 is 1" do
|
||
|
|
expect(climb_stairs(1)).to eq(1)
|
||
|
|
end
|
||
|
|
|
||
|
|
it "2 is 2" do
|
||
|
|
expect(climb_stairs(2)).to eq(2)
|
||
|
|
end
|
||
|
|
|
||
|
|
it "3 is 3" do
|
||
|
|
expect(climb_stairs(3)).to eq(3)
|
||
|
|
end
|
||
|
|
end
|