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Tested Python solution for LeetCode 367 with 21 pytest cases. Generate a practice environment with lcpy.
lcpy gen -n 367 # by problem number
lcpy gen -s valid_perfect_square # by problem name
num, return true if num is a perfect square or false otherwise.
A perfect square is an integer that is the square of an integer. In other words, it is the product of some integer with itself.
You must not use any built-in library function, such as sqrt.
Input: num = 16
Output: true
Explanation: We return true because 4 * 4 = 16 and 4 is an integer.
Input: num = 14
Output: false
Explanation: We return false because 3.742 * 3.742 = 14 and 3.742 is not an integer.
class Solution:
# Time: O(log num)
# Space: O(1)
def is_perfect_square(self, num: int) -> bool:
low, high = 1, num
while low <= high:
mid = (low + high) // 2
squared = mid * mid
if squared == num:
return True
if squared < num:
low = mid + 1
else:
high = mid - 1
return False
| Time | Space |
|---|---|
| O(log num) | O(1) |