Triplet Sum in Array 🎯

Welcome to our lesson on finding Triplets with a given sum in an array! This lesson is designed for both beginners and intermediate learners. Let's dive in!

What is a Triplet Sum? 📝

In the context of an array, a triplet is a combination of three numbers such that their sum equals a given value. For example, in the array [4, 5, 6, 9, 10], a triplet that sums to 15 is [4, 5, 6].

Understanding the Problem 💡

Given an array of integers and a target sum, the task is to find a triplet in the array whose sum is equal to the given target. The order of the triplet in the array matters.

Breaking Down the Problem 📝

To solve this problem, we can follow these steps:

Sort the given array in ascending order.
Iterate through the array with a sliding window approach.
For each window (three elements), check if the sum of the three elements equals the target sum.

Code Example 📝

Here's a Python example that implements the solution:

python

def find_triplet(arr, target_sum):
    arr.sort()
    for i in range(len(arr) - 2):
        left = i + 1
        right = len(arr) - 1

        while left < right:
            if arr[i] + arr[left] + arr[right] == target_sum:
                return [arr[i], arr[left], arr[right]]
            elif arr[i] + arr[left] + arr[right] > target_sum:
                right -= 1
            else:
                left += 1

    return "No such triplet found"

arr = [4, 5, 6, 9, 10]
target_sum = 15
print(find_triplet(arr, target_sum))

Quiz Time 💡

Question: What is the triplet in the array [1, 5, 3, 4, 6] that sums to 8?

Answer: [1, 3, 4]

Wrapping Up 📝

In this lesson, we learned how to find a triplet in an array that sums to a given target. We understood the problem, broke it down, and implemented a solution in Python.

Remember, practice makes perfect! Try implementing this solution in other programming languages or challenge yourself by modifying the problem to find a triplet that sums to a smaller or larger number. Happy coding! 💻🌍🌟