什么是斐波那契数列
数列: 1 1 2 3 5 8 13 21 34 55 … x
位置: 1 2 3 4 5 6 7 8 9 10 … n

    // 1.斐波那契的递归实现function fibonacci(n) {if (n === 1 || n === 2) return 1return fibonacci(n-1) + fibonacci(n-2)}

  // 2.斐波那契的for循环实现function fibonacci(n) {// 特殊的情况(前两个数字)if (n === 1 || n === 2) return 1// for循环的实现var n1 = 1var n2 = 1var result = 0for (var i = 3; i <= n; i++) {result = n1 + n2n1 = n2n2 = result}return result}console.log(fibonacci(5))console.log(fibonacci(10))console.log(fibonacci(20))