40 lines
609 B
Ruby
40 lines
609 B
Ruby
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# @param {Integer} n
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# @return {Integer}
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def fib(n)
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if n == 0 then
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return 0
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end
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prev, current = 0, 1
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(2..n).each {
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prev, current = current, prev + current
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}
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return current
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end
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RSpec.describe "fib of " do
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it "0 is 0" do
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expect(fib(0)).to eq(0)
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end
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it "1 is 1" do
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expect(fib(1)).to eq(1)
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end
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it "2 is 1" do
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expect(fib(2)).to eq(1)
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end
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it "3 is 2" do
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expect(fib(3)).to eq(2)
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end
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it "4 is 3" do
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expect(fib(4)).to eq(3)
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end
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it "5 is 5" do
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expect(fib(5)).to eq(5)
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end
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end
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