# Depth-First Search

## What is it?

Depth-First Search is a tool that helps you find a path between two nodes in a graph by exploring the nodes in a depth-first manner.

**How can it be useful to you?** When you're exploring a network or graph and want to dive as deep as possible along a branch before retracing steps and exploring other branches.

## The Maze Explorer

Suppose you're navigating a labyrinth and want to find the exit. You pick a path and follow it as far as you can go. If you hit a dead-end, you backtrack to the previous junction and choose a different path. This process continues until you find the exit or have explored all paths. This approach, where you explore as deep as possible along a path before backtracking, mirrors the DFS algorithm.

## The Family Tree

Let's say you're researching your family tree and want to trace your lineage as far back as possible. You would start with your parents, then trace back through your paternal line as far as you can go. If you reach a point where you can't trace any further, you'd backtrack and then explore your maternal line, again going as far back as possible. This method, where you trace as far back as possible along one branch before moving to another, is an example of DFS.

## The Book Search

Imagine you're in a library, looking for a book, but you don't know which shelf it's on. You ...