<div id="div7"><h4> 7, 斐波那契数列 <h4></div> ```javascript function Fibonacci(n) { let f = 0, g = 1; while (n--) { g += f; f = g - f; } return f; } ``` <div id="div8"><h4> 8, 跳台阶 <h4></div> ```javascript function jumpFloor(number) { let f = 1, g = 2; while (--number) { g += f; f = g - f; } return f; } ``` <div id="div9"><h4> 9, 变态跳台阶 <h4></div> ```javascript function jumpFloorII(number) { let i = 1; while (--number) { i *= 2; } return i; } ``` <div id="div10"><h4> 10, 矩形覆盖 <h4></div> ```javascript function rectCover(number) { if (number === 0) return 0; let f = 1, g = 2; while (--number) { g += f; f = g - f; } return f; } ```