1.小平方

代码

n = int(input())
count=0
def f(x)->bool: # 判断条件
    return True if x**2%n<n/2 else False
for i in range(1,n): # 遍历[1,n-1]，符合题意计数加一
    if f(i):
        count+=1
print(count)

2.3的倍数

代码

a = int(input())
b = int(input())
c = int(input())
if (a+b)%3==0 or (a+c)%3==0 or (b+c)%3==0:
    print('yes')
else:
    print('no')

3.格点

代码

count=0
for i in range(1,2022):
    for j in range(1,2022):
        if i*j<=2021:
            count+=1
print(count)