试题A：门牌制作

代码：

ans = []
for i in range(1,2020+1):
	if '2' in str(i):
    	ans.append(str(i).count('2'))
print(sum(ans))

结果：624

试题B：既约分数

代码：

def gcd(x,y):
	if y==0:
		return x
	else:
		return gcd(y,x%y)
		
ans = 0
for i in range(1,2020+1):
	for j in range(1,2020+1):
		if gcd(i,j) == 1:
			ans += 1
print(ans)

结果：2481215

试题C：蛇形填数

代码：

ans = 1
for i in range(20):
	ans += i * 4
print(ans)

结果：761
链接: link.

试题D：跑步锻炼

代码：

from datetime import date
from datetime import timedelta

start = date(2000, 1, 1)
end = date(2020, 10, 2)

res = 0
while start < end:
	res += 2 if start.day == 1 or start.weekday() == 0 else 1
	start += timedelta(days=1)
print(res)

结果：8879
链接: link.

试题E：七段码

代码：

import numpy as np
import itertools as it


class UnionFind:
    def __init__(self, n):
        self.father = list(range(n))
        self.size = [1] * n
        # 当前连通分量数目
        self.setCount = n

    def find(self, x):
        if self.father[x] == x:
            return x
        self.father[x] = self.find(self.father[x])
        return self.father[x]

    def merge(self, x, y):
        x, y = self.find(x), self.find(y)
        if x == y:
            return False
        if self.size[x] < self.size[y]:
            x, y = y, x
        self.father[y] = x
        self.size[x] += self.size[y]
        self.setCount -= 1
        return True
    

res = 0
data = list(np.zeros((7, 7)))

data[0][1] = data[0][5] = 1
data[1][0] = data[1][6] = data[1][2] = 1
data[2][1] = data[2][3] = data[2][6] = 1
data[3][2] = data[3][4] = 1
data[4][3] = data[4][5] = data[4][6] = 1
data[5][0] = data[5][4] = data[5][6] = 1

num = [i for i in range(0, 7)]

for i in range(1, 8):
    total = it.combinations(num, i)
    for j in total:
        uf = UnionFind(7)

        for z in j:
            for k in range(len(data[z])):
                z = int(z)
                b = int(data[z][k])
                if b == 1 and k in j:
                    uf.merge(z, k)

        if uf.setCount == 7 - len(j) + 1:
            res += 1

print(res)

结果：80
链接: link.

试题F：成绩统计

代码：

n = int(input())
num1 = 0
num2 = 0
for i in range(n):
    stu = int(input())
    if stu >= 60:
        num1 += 1
    if stu >= 85:
        num2 += 1
print('{:d}%'.format(round(num1/n*100)))
print('{:d}%'.format(round(num2/n*100)))

链接: link.

试题G：回文日期

代码：

st_time=input()
year=int(st_time[0:4])
big_month=[1,3,5,7,8,10,12]
flag1=0
flag=0
while(True):
    s=str(year)
    time=s+s[::-1]
    month=int(time[4:6])
    day=int(time[6:8])
    if(flag==0):
        if(month<int(st_time[4:6]) or day<int(st_time[6:8])):
            flag=1
            year+=1
            continue
    if(big_month.count(month)==1):
        if(month<=12 and month>0 and day<=31 and day>0 and flag1==0):
            time1=time
            flag1=1
        if(month<=12 and month>0 and day<=31 and day>0
           and s[0]==s[2] and s[1]==s[3]):
            time2=time
            break
    else:
        if(month==2):
            if(year%400==0 or (year%4==0 and year%100!=0)):
                if(month<=12 and month>0 and day<=29 and day>0 and flag1==0):
                    time1=time
                    flag1=1
                if(month<=12 and month>0 and day<=29 and day>0
                       and s[0]==s[2] and s[1]==s[3]):
                        time2=time
                        break
            else:
                if(month<=12 and month>0 and day<=28 and day>0 and flag1==0):
                    time1=time
                    flag1=1
                if(month<=12 and month>0 and day<=28 and day>0
                       and s[0]==s[2] and s[1]==s[3]):
                        time2=time
                        break
        else:
            if(month<=12 and month>0 and day<=30 and day>0 and flag1==0):
                time1=time
                flag1=1
            if(month<=12 and month>0 and day<=30 and day>0
                   and s[0]==s[2] and s[1]==s[3]):
                    time2=time
                    break
    year+=1
    flag=1
print(int(time1))
print(int(time2))

链接: link.

试题H：子串分值和

代码：

list1=list(input())
list2=[-1 for i in range(26)]
count=0

for i in range(len(list1)):
    index=ord(list1[i])-ord('a')
    count+=(len(list1)-i)*(i-list2[index])
    list2[index]=i

print(count)

链接: link.

试题I：平面切分

代码：

N=int(input())
input_lis=[]
crosspoint_x_set=set()

for i in range(N):
    input_lis.append(list(map(int,input().split())))
input_lis=list(set([tuple(t) for t in input_lis]))	#去掉重合的线段
each_line_num_lis = [1] * (len(input_lis) + 1)	
for i in range(1,len(input_lis)):
    crosspoint_x_set.clear()#crosspoint_x_set计算的第n条直线与前面直线的交点x，我们只需要的是set的长度，算出长度之后作为N加，然后clear，继续计算下一个条直线与前面直线的交点x
    for n in range(i):
        if input_lis[i-n-1][0]!=input_lis[i][0]:
            x=round((input_lis[i][1]-input_lis[i-n-1][1])/(input_lis[i-n-1][0]-input_lis[i][0]),4)
            crosspoint_x_set.add(x)
    each_line_num_lis[i] += len(crosspoint_x_set)
print(sum(each_line_num_lis) )