尾递归（斐波那契数列）

[Sunny Fu]

[weirong111]

function Fibonacci(n,num=1,sum=1){

    if (n<=2){
        return sum;
    }
    return Fibonacci(n-1,sum,num+sum);
}

[weirong111]

function feibo3(n) {
  let pre = 1;
  let cur = 1;
  for (let i = 2; i <= n; i++) {
    [pre, cur] = [cur, cur + pre];
  }
  return cur;
}

[fantasticbin]

function fibonacci(n) {
    if (n <= 2) {
        return n;
    }

    return fibonacci(n - 1) + fibonacci(n - 2);
}