劍指offer(10)--------斐波那契與蛙跳

def fib(n):
    if n <= 1:
        return n
    return fib(n-1) + fib(n-2)

def fib_no_recusive(n):
    if n <= 1:
        return n
    i, j, k, r = 0, 1, 2, 0
    while k <= n:
        r = i + j
        k += 1
        i, j = j, r
    return r

def frog_jump(n):
    if n <= 2:
        return n
    i, j, k, r = 1, 2, 3, 0
    while k <= n:
        r = i + j
        k += 1
        i, j = j, r
    return r

if __name__ == "__main__":
    print(fib(3))
    print(fib(10))
    print(fib_no_recusive(3))
    print(fib_no_recusive(10))
    print(fib_no_recusive(100))

    print(frog_jump(2))
    print(frog_jump(3))
    print(frog_jump(10))