python学习 2数学公式

def fact(n):
if n <= 1:
return 1
else:
return n * fact(n - 1)

def fib(n):
i = 2
arr = [0, 1]
while n > 2:
arr.append(arr[i - 1] + arr[i - 2])
n -= 1
i += 1
return arr

//
MemoTable = {}

def MemoizedFib(n):
if n <= 2:
return 1

if n in MemoTable:
return MemoTable

MemoTable
= MemoizedFib(n-1) + MemoizedFib(n-2)
return MemoTable

def sqrt(x):
def average(a, b):
return (a + b) / 2.0

def is_good_enough(guess):
return (abs((guess * guess) - x) < 0.001)

def improve(guess):
return average(guess, x / guess)

def sqrt_iter(guess):
if is_good_enough(guess):
return guess
else:
return sqrt_iter(improve(guess))

return sqrt_iter(1.0)

def gcd(x, y):
result = x
if y != 0:
result = gcd(y, x % y)
return result

def TowerOfHanoi(n, a, b, tmp):
if n == 1:
b.append(a.pop())
else:
TowerOfHanoi(n-1, a, tmp, b)
b.append(a.pop())
TowerOfHanoi(n-1, tmp, b, a)

stack1 = [4,3,2,1]
stack2 = []
stack3 = []

TowerOfHanoi(len(stack1), stack1, stack3, stack2)

def map(func, lst):
if lst == []:
return []
else:
return [func(lst[0])] + map(func, lst[1:])

def halveElements(lst):
return map(lambda x: x / 2.0, lst)

input = [2, 4, 6, 8, 10]
output = halveElements(input)

def summation(low, high, f, next):
s = 0
x = low
while x <= high:
s = s + f(x)
x = next(x)
return s

def sumsquares(low, high):
return summation(low, high, lambda x: x**2, lambda x: x+1)