蓝桥杯刷题（十三）

1.煤球数目

代码

cnt = ans = 0
start = 1
a = []
while cnt<100:
    ans+=start
    start += 1
    t = ans+start
    cnt+=1
    a.append(ans)
print(sum(a))

2.奖券数目

代码

def f(x)->bool:
    while x:
        if x%10==4:
            return False
        x//=10
    return True
ans = 0
for i in range(10000,100000):
    if f(i):
        ans+=1
print(ans)

3.网友年龄

代码

def f(x):
    return int(str(x)[::-1])
ans=0
for i in range(10,100):
    if f(i)==i-27:
        ans+=1
print(ans)

4.方程整数解

代码

for i in range(1,33):
    for j in range(i,33):
        for k in range(j,33):
            if i*i+j*j+k*k==1000 and min(i,j,k)!=6:
                print(min(i,j,k))

5.回家路费

代码

i = cnt =1
t = 2
while i < 108:
    i += t
    t +=2
    cnt+=1
print(cnt)

6. 质数

代码

def f(x)->bool:
    for i in range(2,x//2+1):
        if x%i==0:
            return False
    return True
ans=[2]
for i in range(3,20000):
    if f(i):
        ans.append(i)
    if len(ans)==2019:
        break
print(ans[-1])

7.猜年龄

代码

ans=[]
for i in range(1,30):
    for j in range(i,30):
        if i*j//(i+j)==6 and j-i<=8:
            ans.append(i)
print(ans[0])