DEV Community

kingyou
kingyou

Posted on

Graphs — Kids' Friendship Map Adventure!

#basic #tutorial #datastructures

Imagine your classmates holding hands in a big circle, or like a spider web connecting everyone. That's a graph! It's like a super cool friendship map showing who knows who. Today let's draw this fun map — as easy as playing connect-the-dots!

Graphs: Who's Friends with Who?

A graph is like a big piece of paper with dots (nodes) for kids, connected by lines (edges) for friendships!

Everyday examples:

  • Classroom seating: Tom connects to Lily, Lily to Jack
  • Subway map: Station A links to B, B to C
  • Social media: You follow Mia, Mia follows Sam

Draw a simple graph:

   Tom —— Lily
    |     /
    |    /
   Jack
Enter fullscreen mode Exit fullscreen mode

Tom, Lily, and Jack are all friends!

Two Fun Ways to Play Graphs

1. One-way graphs (like one-way streets):

Tom → Lily → Jack
Enter fullscreen mode Exit fullscreen mode

Tom knows Lily, Lily knows Jack, but Jack might not know Tom back.

2. Two-way graphs (like two-way roads):

Tom ↔ Lily ↔ Jack
Enter fullscreen mode Exit fullscreen mode

Everyone's best buddies both ways!

Super Easy Code to Try (Python) 

# Friendship map
friends = {
    "Tom": ["Lily", "Jack"],  # Tom's friends
    "Lily": ["Tom", "Jack"],  # Lily's friends
    "Jack": ["Tom", "Lily"]   # Jack's friends
}

# See Tom's friends
print("Tom's friends:", friends["Tom"])  # ['Lily', 'Jack']

# Find mutual friends
tom_friends = friends["Tom"]
lily_friends = friends["Lily"]
mutual = set(tom_friends) & set(lily_friends)
print("Tom and Lily's mutual friend:", mutual)  # {'Jack'}
Enter fullscreen mode Exit fullscreen mode

How to Play the Friendship Map Game?

Get started:

  1. Open Python (or python.org online)
  2. Save code as friendship_map.py
  3. Run: python friendship_map.py in command line

What you'll see:

Tom's friends: ['Lily', 'Jack']
Tom and Lily's mutual friend: {'Jack'}
Enter fullscreen mode Exit fullscreen mode

Add your classmates' names and find shared friends!

Graphs Help Everywhere in Life!

  • Social apps: "You have 3 mutual friends"
  • Map apps: Shortest path (A→B→D is fastest)
  • Games: Quickest way to treasure

You're a friendship map master now! Draw your class web or tweak the code to find the "most popular kid." So much fun! 🕸️✨

Top comments (0)