How do you solve Is Object Empty on LeetCode?

Is Object Empty (LeetCode #2727) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(1) space complexity. Key insight: Understanding the difference between objects and arrays is crucial for checking emptiness.

What is the brute force solution for Is Object Empty?

The brute force approach for Is Object Empty is Brute Force, with O(n) time complexity and O(1) space complexity. The brute force approach checks the length of the object or array directly. If it's an object, we can count its keys; if it's an array, we check its length. This is straightforward but not efficient. The optimal Optimal Solution approach improves this to O(n).

What are the interview tips for Is Object Empty?

Always clarify the input type before starting your solution. Discuss your thought process out loud to show your understanding. Consider edge cases and test your solution with them.

What are common mistakes when solving Is Object Empty?

Confusing the checks for arrays and objects. Not handling edge cases like null or non-iterable types.

#2727

Is Object Empty

Easy

Hash MapArray

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n)	O(n)
Space	O(1)	O(1)

💡

Intuition

Time O(n)Space O(1)

The optimal solution leverages the built-in methods to check for emptiness directly, which is efficient and clear. We can handle both objects and arrays in a single function call.

⚙️

Algorithm

3 steps

1Step 1: Check if the input is an array using Array.isArray().
2Step 2: If it's an array, return its length check.
3Step 3: If it's an object, return the result of Object.keys() length check.

solution.py2 lines

1def is_empty(obj):
2    return (isinstance(obj, list) and len(obj) == 0) or (isinstance(obj, dict) and len(obj) == 0)

ℹ

Complexity note: The optimal solution has a time complexity of O(n) because we still need to check the length of the keys or elements, but it is more concise and clear.

1Understanding the difference between objects and arrays is crucial for checking emptiness.
2Using built-in functions like Object.keys() and Array.isArray() simplifies the code.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.