ELI5Code — Zero / Hero Coding Bootcamp

Lessons build recognition; a project builds ability. Pick ONE, build it in Python or JavaScript on your own machine, and tick the milestones as they genuinely work. Every step maps to lessons you have already completed.

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Task Scheduler

priority queues · hash maps · graphs · topological sort

Build a command-line task manager where tasks have priorities and dependencies. It must always suggest the most urgent task whose prerequisites are done.

Model a Task (id, title, priority, dependsOn[]) and store tasks in a hash map by id — O(1) lookupKeep a ready-queue as a heap/priority queue ordered by priorityDetect dependency cycles with DFS before accepting a new taskTopologically sort the whole board into a valid work orderMeasure it: add 10,000 fake tasks and confirm suggest-next stays under a millisecond

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Search Autocomplete

tries · strings · sorting · sliding window

Type two letters, get the top suggestions instantly — like a search box. Works on a dictionary of 10,000+ words.

Load a word list into a trie; each node stores its subtree's best-ranked completionsReturn top-5 completions for any prefix in O(prefix length)Add fuzzy matching for one typo using edit distance (DP!)Track trending searches with a sliding-window counter of recent queriesCompare against a naive linear scan and chart both at n = 100 / 1k / 10k words

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Grid Pathfinder

graphs · BFS · Dijkstra · A* · heaps

A maze on a grid with walls and mud (slow cells). Find the best route — then find it faster.

Model the grid as a graph: cells are nodes, moves are edges (mud costs 3)BFS for shortest path when every step costs 1; reconstruct and print the routeDijkstra with a priority queue once mud enters the pictureUpgrade to A* with the Manhattan-distance heuristic and count visited cells vs DijkstraAnimate the frontier in the terminal — watch the ripple, just like the visualizer

Capstone projects

Task Scheduler

Search Autocomplete

Grid Pathfinder