Description
Given an integer n, return true if n has exactly three positive divisors. Otherwise, return false.
An integer m is a divisor of n if there exists an integer k such that n = k * m.
Example 1:
Input: n = 2 Output: false Explantion: 2 has only two divisors: 1 and 2.
Example 2:
Input: n = 4 Output: true Explantion: 4 has three divisors: 1, 2, and 4.
Constraints:
1 <= n <= 104
Solution
Python3
class Solution:
def isThree(self, n: int) -> bool:
res = 0
for k in range(1, n + 1):
if n % k == 0: res += 1
if res > 3: return False
return res == 3