斐波那契数

题目

求斐波那契数.

示例

输入: 10

输出: 5

题解

关于斐波那契数的各种花式玩法, 可参考动态规划.

/**
 * @param {number} N
 * @return {number}
 */
var fib = function (N) {
  if (N <= 1) return N

  let prev = 0
  let curr = 1

  for (let i = 2; i <= N; i++) {
    const sum = prev + curr
    prev = curr
    curr = sum
  }
  return curr