Project Euler Problem 2
問題
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, ... Find the sum of all the even-valued terms in the sequence which do not exceed four million.
ソース
sum = 0 x = 1 y = 2 while x <= 4000000 do x, y = y, x + y sum += x if x % 2 == 0 end p sum
解答
4613732
感想
なぜ2が入らないのかが未だに謎。。。