Learn essential coding patterns to answer problems and prepare for tech companies' interviews.

Ace the JavaScript Coding Interview

This module teaches us the underlying patterns behind common coding interview questions. By learning these essential patterns, we'll be able to unpack and answer any problem the right way—just by assessing the problem statement. This approach was created by FAANG hiring managers to help us prepare for the typical rounds of interviews at major tech companies like Apple, Google, Meta, Microsoft, and Amazon.

By the end of this module, we'll have the skills we need to unlock even the most challenging questions, grok the coding interview, and level up our career with confidence.

Coding Interview Patterns

# Statement

Given an array `nums` of $n$ integers, return an array of all the unique quadruplets, [`nums[a]`, `nums[b]`, `nums[c]`, `nums[d]`] such that:

- $0 \leq$ `a`, `b`, `c`, `d` $< n$

- `a`, `b`, `c`, and `d` are distinct.

- `nums[a]` + `nums[b]` + `nums[c]` + `nums[d]` $=$ `target`

You may return the answer in any order.

**Constraints:**

- $1 \leq$ `nums.length` $\leq 200$

- $-10^9 \leq$ `nums[i]` $\leq 10^9$

- $-10^9 \leq$ `target` $\leq 10^9$

# Examples


4Sum

Statement