Cracking LeetCode 2784: Is This Array "Good"? Let's Find Out!

Hey everyone! Vansh2710 here, your friendly neighborhood competitive programmer and technical writing enthusiast! Today, we're diving into a fun little LeetCode problem that's perfect for beginners to sharpen their logical thinking: 2784. Check if Array is Good .

Don't let the "permutation" jargon scare you. We'll break it down step by step and discover an elegant solution together. Ready to level up your LeetCode game? Let's go!

🚀 Problem Explanation: What Makes an Array "Good"?

Imagine you have a special kind of array called base[n] . This base[n] array always looks like this:

[1, 2, ..., n - 1, n, n]

In plain English, it's an array of length n + 1 that contains:

All numbers from 1 up to n - 1 appear exactly once .

The number n appears exactly twice .

For example:

If n = 1 , then base[1] = [1, 1] . (Length 1+1=2)

If n = 3 , then base[3] = [1, 2, 3, 3] . (Length 3+1=4)

If n = 5 , then base[5] = [1, 2, 3, 4, 5, 5] .…