How do you solve Add Two Promises on LeetCode?

Add Two Promises (LeetCode #2723) 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 how promises work is crucial for handling asynchronous operations.

What is the brute force solution for Add Two Promises?

The brute force approach for Add Two Promises is Brute Force, with O(n) time complexity and O(1) space complexity. The brute-force approach involves waiting for both promises to resolve and then adding their results together. This is straightforward but not the most efficient way to handle promises. The optimal Optimal Solution approach improves this to O(n).

What are the interview tips for Add Two Promises?

Explain your thought process clearly while coding. Be prepared to discuss the implications of asynchronous programming. Practice writing promises and handling their resolutions.

What are common mistakes when solving Add Two Promises?

Forgetting to return the new promise. Not handling errors that may arise from the promises.

#2723

Add Two Promises

Easy

Promise HandlingAsynchronous Programming

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 approach also uses Promise.all but emphasizes the efficiency of handling promises without unnecessary waiting or chaining, ensuring we get the sum directly.

⚙️

Algorithm

3 steps

1Step 1: Use Promise.all to handle both promises concurrently.
2Step 2: Once resolved, destructure the results to get the values directly.
3Step 3: Return the sum of the values immediately.

solution.py2 lines

1def add_two_promises(promise1, promise2):
2    return Promise.all([promise1, promise2]).then(lambda a, b: a + b)

ℹ

Complexity note: The time complexity remains O(n) as we still wait for both promises. The space complexity is O(1) since we are not storing additional data.

1Understanding how promises work is crucial for handling asynchronous operations.
2Using Promise.all allows for concurrent resolution of multiple promises.

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