算法基本整理

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#算法基本整理

def func2(n):
if n > 0:
func2(n - 1)
print(n)


# func2(2)
# 输出2
# func2(1)
# 输出1
# func2(0)
# 没有输出
# func2(2)

# print("====", end="\n")
# print("====", end="")

def func3(n):
if n > 0:
print("抱着", end="")
func3(n - 1)
print("的我", end="")
else:
print("我的小鲫鱼", end="")


# func3(3)
# 输出 抱着
# func3(2)
# 再输出 抱着
# func3(1)
# 再输出 抱着
# func3(0)
# 输出 我的小鲫鱼
# 的我
# 的我
# 的我

# func3(3)
import time


def cal_time(func):
def inner(*args, **kwargs):
start = time.time()
ret = func(*args, **kwargs)
stop = time.time()
temp = stop - start
print(f'函数执行了{temp}秒')
return ret

return inner


def fbnqxl(n):
if n == 0 or n == 1:
return 1
else:
return fbnqxl(n - 1) + fbnqxl(n - 2)


@cal_time
def fib1(n):
return fbnqxl(n)


@cal_time
def fib2(n):
li = [1, 1]
for i in range(2, n + 1):
# li.append(li[i - 1] + li[i - 2])
li.append(li[-1] + li[-2])
return li[n]


# 1 1 2 3 5 8

@cal_time
def fib3(n):
a = 1
b = 1
c = 1
for i in range(2, n + 1):
c = a + b
a = b
b = c
return c


# print(fib1(20))
# print(fib2(10000))
# print(fib3(10))