2022第十三届蓝桥杯国赛PythonB组_python中b组蓝桥杯斐波那契与7代码及思路

题目很好，是我太菜了，呜呜呜
就放点题目了，题解我不配

A斐波那契与 7

思路：打表找规律，周期应该是60

给出的那个数也正好是60的倍数，代码如下：

a = 1
b = 1
n = 202202011200
cnt = 0
for i in range(58):
    c = a+b
    if c % 10 == 7:
        cnt += 1
    a = b
    b = c

res = cnt*(n//60)
print(res)
# 26960268160

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

B小蓝做实验

思路：一边判断一边筛，结合python的字典

from math import *


def isPrime(n):
    for i in range(2, int(sqrt(n))+1):
        if n % i == 0:
            return False
    return True


dic = {}
with open('primes.txt', 'r') as file:
    txt = file.readlines()

cnt = 0
for num in txt:
    num = int(num[:-1])
    if num in dic:
        if dic[num]:
            cnt += 1
    else:
        if isPrime(num):
            cnt += 1
            dic[num] = True
        else:
            dic[num] = False
        tmp = num*2
        while tmp <= 10**8:
            dic[tmp] = False
            tmp += num


print(cnt)
print('end')
# 342693

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36

C取模

D内存空间

E近似 GCD

F交通信号

G点亮

H打折

Iowo

J替换字符