Скачать или смотреть LeetCode 326 Power of Three in Python | Easy Coding Tutorial for Beginners

Solve LeetCode 326 "Power of Three" in Python with this beginner-friendly coding tutorial! This problem asks you to determine if a given integer `n` is a power of 3, i.e., if there exists an integer `k` such that `n = 3^k` (e.g., n = 27 returns true). We’ll use a set comprehension to check if `n` matches any power of 3, and explore alternative methods like logarithmic and mathematical approaches. Perfect for Python learners, coding beginners, or anyone prepping for coding interviews!

🔍 *What You'll Learn:*
Understanding LeetCode 326’s requirements
Using a set comprehension to check powers of 3
Exploring alternative solutions with logarithms and mathematical properties
Testing with example cases

💻 *Code Used in This Video:*
class Solution(object):
def isPowerOfThree(self, n):
"""
:type n: int
:rtype: bool
"""
return n in {3**i for i in range(20)}

Test cases
solution = Solution()

Test case 1: A power of 3
print(solution.isPowerOfThree(27)) # Output: True
27 = 3^3, so it’s a power of 3

Test case 2: Not a power of 3
print(solution.isPowerOfThree(45)) # Output: False
45 is not a power of 3

Test case 3: Edge case (n = 1)
print(solution.isPowerOfThree(1)) # Output: True
1 = 3^0, so it’s a power of 3

Test case 4: Zero and negative numbers
print(solution.isPowerOfThree(0)) # Output: False
0 is not a power of 3
print(solution.isPowerOfThree(-3)) # Output: False
Negative numbers are not powers of 3

Alternative: Mathematical solution (no loops)
class SolutionOptimized(object):
def isPowerOfThree(self, n):
"""
:type n: int
:rtype: bool
"""
A number n is a power of 3 if 3^19 % n == 0 (since 3^19 is the largest power of 3 in 32-bit int range)
return n {greater than} 0 and 1162261467 % n == 0 # 1162261467 = 3^19

solution_opt = SolutionOptimized()
print("\nOptimized solution:")
print(solution_opt.isPowerOfThree(27)) # Output: True
print(solution_opt.isPowerOfThree(45)) # Output: False

🌟 *Why Solve LeetCode 326?*
This problem is a great introduction to number theory and optimization in Python, a common topic in coding interviews! The set comprehension solution has a time complexity of O(1) since the range is fixed, but the optimized mathematical solution is even more efficient, also O(1) with O(1) space complexity. We’ll explore both methods to determine if a number is a power of 3. Master this, and you’ll be ready for more advanced LeetCode challenges!

📚 *Who’s This For?*
Python beginners learning coding
Coding enthusiasts tackling LeetCode problems
Developers prepping for technical interviews

👍 Like, subscribe, and comment: What LeetCode problem should we solve next? Next up: More LeetCode number theory problems—stay tuned!

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