What is the Two Sum problem in programming?

Can you explain what the Two Sum problem is?

The Two Sum problem is a classic algorithmic challenge where you need to find two numbers in an array that add up to a specific target.

How would you solve it using Python?

You can solve it using a dictionary to store the numbers and their indices. Here's a simple implementation:

def two_sum(nums, target):
    num_map = {}
    for i, num in enumerate(nums):
        complement = target - num
        if complement in num_map:
            return [num_map[complement], i]
        num_map[num] = i

What is the time complexity of this solution?

The time complexity of this solution is O(n), where n is the number of elements in the array, because we traverse the list once.

Are there any other approaches to solve the Two Sum problem?

Yes, you can also use a brute force approach with a time complexity of O(n^2) by checking all pairs of numbers.