Lua Implementation of Problem 2

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Solution

solution()

Returns:

The solution to problem 2

Return type:

number

-- Project Euler Problem 2
--
-- I modeled this after the C++ solution, because it was by far the simplest
--
-- Problem:
--
-- Each new term in the Fibonacci sequence is generated by adding the previous two
-- terms. By starting with 1 and 2, the first 10 terms will be:
--
-- 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
--
-- By considering the terms in the Fibonacci sequence whose values do not exceed
-- four million, find the sum of the even-valued terms.

return {
    solution = function()
        local answer = 0
        local a = 1
        local b = 2

        while b < 4000000 do
            answer = answer + b

            for _ = 1,3 do
                a, b = b, a + b
            end
        end

        return answer
    end
}

Tags: divisibility, fibonacci-number