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Welcome to the iwantcoding.com Data Structures & Algorithms Tutorial. Data Structures & Algorithms — the toolbox every interviewer asks about. This track teaches the patterns you actually need to recognise on the job: pick the right structure first, and the algorithm often falls out for free.
What this tutorial covers
| Chapter | You will learn |
|---|---|
| Foundations | Big-O, arrays, strings, linked lists, stacks, queues, hash maps / sets, trees, BSTs, heaps, graphs, tries, union-find. |
| Sorting & Searching | Binary search, classic sorts, merge / quick / heap, counting / radix. |
| Algorithms | Two pointers, sliding window, recursion, backtracking, DP, greedy, divide & conquer, BFS, DFS, Dijkstra, topo sort, bit manipulation. |
| Interview Prep | Pattern catalogue, complexity cheatsheet, LeetCode roadmap, system design intro. |
| Examples | Cheatsheet, runnable snippets, quiz, exercises, bootcamp, certificate. |
Who this is for
- Engineers prepping for interviews.
- CS students reinforcing fundamentals.
- Senior devs refreshing patterns before a tech screen.
How to use this tutorial: read the chapter, run the example with Try it Yourself », do the exercise, then take the quiz at the bottom. Hit Mark complete when you're done — the sidebar will track your progress.
Example
Example
// Two-sum in O(n)
function twoSum(nums, target) {
const seen = new Map();
for (let i = 0; i < nums.length; i++) {
const need = target - nums[i];
if (seen.has(need)) return [seen.get(need), i];
seen.set(nums[i], i);
}
return [];
}
Try it Yourself »
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