### 斐波那契數列 >斐波那契數列：1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ...前兩位均為1，后面每一位等于前兩位的和，求第n位的值，或者前n位的和 1. 遞歸 ``` function fib(n){ if(n==1 || n==2){ return 1; } return fib(n-1) + fib(n-2); } // console.log(fib(3)); for(let i=1; i<=10; i++){ console.log(fib(i)); } ``` 2. 迭代法 ``` function getNthFibonacci(count) { if(count<0) return 0; if(count<=1) return 1; var first = 1; var second = 1; var third = 0; for(var i = 2; i <= count; i++) { third = first + second; first = second; second = third; } return third; } ```