JavaScript:实现1000 位斐波那契数算法
/**
*
* The Fibonacci sequence is defined by the recurrence relation:
*
* Fn = Fn−1 + Fn−2, where F1 = 1 and F2 = 1.
*
* Hence the first 12 terms will be:
*
* F1 = 1
* F2 = 1
* F3 = 2
* F4 = 3
* F5 = 5
* F6 = 8
* F7 = 13
* F8 = 21
* F9 = 34
* F10 = 55
* F11 = 89
* F12 = 144
* The 12th term, F12, is the first term to contain three digits.
* What is the index of the first term in the Fibonacci sequence to contain 1000 digits?
*/
// brute force method
function fibonacciIndex (