Question 1

What is the fast and slow pointer technique?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — no prior algorithms knowledge assumed
**Difficulty:** Easy
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. All code is Python, and every output block in the **Verified** section was copied from a real run of the examples on this page.

## 1. Why This Even Matters — A Story First

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Question 2

How do you find the intersection node of two linked lists?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — you should know what a linked list node is; everything else is explained
**Difficulty:** Easy
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. All code is Python, and every output block in the **Verified** section was copied from a real run of the examples on this page.

## 1. Why This E

Question 3

How do you find the middle of a linked list?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — no prior algorithms knowledge assumed
**Difficulty:** Easy
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. All code is Python, and every output block in the **Verified** section was copied from a real run of the examples on this page.

## 1. Why This Even Matters — A Story First

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Question 4

How do you move all zeroes to the end of an array in place?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — no prior algorithms knowledge assumed
**Difficulty:** Easy
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. All code is Python, and every output block in the **Verified** section was copied from a real run of the examples on this page.

## 1. Why This Even Matters — A Story First

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Question 5

How do you check if a string is a valid palindrome?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — no prior algorithms knowledge assumed
**Difficulty:** Easy
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. All code is Python, and every output block in the **Verified** section was copied from a real run of the examples on this page.

## 1. Why This Even Matters — A Story First

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Question 6

How do you check if a linked list is a palindrome?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — you should know what a linked list node is; everything else is explained
**Difficulty:** Easy
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. All code is Python, and every output block in the **Verified** section was copied from a real run of the examples on this page.

## 1. Why This E

Question 7

How do you remove the nth node from the end of a linked list?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — you should know what a linked list node is; everything else is explained
**Difficulty:** Medium
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. All code is Python, and every output block in the **Verified** section was copied from a real run of the examples on this page.

## 1. Why This

Question 8

How do you solve the container with most water problem?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — you should know arrays and loops; nothing else is assumed.
**Difficulty:** Medium
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged `📌 Interview term:` with the exact vocabulary an interviewer expects. Every output quoted in the **Verified** section was printed by actually running the code shown with `python3`.

## 1. Why This Even Matters — A Story First

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Question 9

How do you solve the 3Sum problem?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — you should know what an array and a loop are; nothing else is assumed.
**Difficulty:** Medium
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged `📌 Interview term:` with the exact vocabulary an interviewer expects. Every output quoted in the **Verified** section was printed by actually running the code shown with `python3`.

## 1. Why This Even Matters — A Story First

Question 10

What is the two-pointer technique?

Accepted Answer

**Target Audience:** Beginners preparing for coding interviews — no prior algorithms knowledge assumed
**Difficulty:** Medium
**Language:** Python 3

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. All code is Python, and every output block in the **Verified** section was copied from a real run of the examples on this page.

## 1. Why This Even Matters — A Story First

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DATA STRUCTURES & ALGORITHMSDECODED.

Easy

What is the fast and slow pointer technique?

How do you find the intersection node of two linked lists?

How do you find the middle of a linked list?

How do you move all zeroes to the end of an array in place?

How do you check if a string is a valid palindrome?

How do you check if a linked list is a palindrome?

Medium

How do you remove the nth node from the end of a linked list?

How do you solve the container with most water problem?

How do you solve the 3Sum problem?

What is the two-pointer technique?

Hard

How do you solve the trapping rain water problem?