DataWeave programming challenge #4: Solve the Tower of Hanoi mathematical puzzle

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Other posts from this series:

1. DataWeave programming challenge #1: Add numbers separated by paragraphs and get the max number

2. DataWeave programming challenge #2: Rock Paper Scissors game score system

3. DataWeave programming challenge #3: Count palindrome phrases using the Strings module

4. DataWeave programming challenge #4: Solve the Tower of Hanoi mathematical puzzle

5. DataWeave programming challenge #5: Reverse a phrase's words, but keep the punctuation

6. DataWeave programming challenge #6: Using tail-recursion to get the factorial of a number

7. DataWeave programming challenge #7: Modify certain values from a JSON structure

8. DataWeave programming challenge #8: Sum all digits to get a 1-digit number

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In this post:

• Input

• Explanation of the problem

• Expected output

• Clues

• Answer

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This challenge is based on the Tower of Hanoi mathematical puzzle - this is a tough one!

Try to solve this challenge on your own to maximize learning. We recommend you refer to the DataWeave documentation only. Try to avoid using Google or asking others so you can learn on your own and become a DataWeave expert!

⚠️ Important: There are 3 different scenarios to test your code is working properly and to ensure there are no hardcoded values. However, only the first scenario is provided in the Playground link below. Please copy+paste the other two scenarios to make sure your solution is working properly.

Solve on the Playground

Input

Consider the following JSON inputs:

SCENARIO 1

{
    "moves": 0,
    "disks": 3,
    "targetTower": "C",
    "towers": {
        "A": [
            1,
            2,
            3
        ],
        "B": [],
        "C": []
    }
}

SCENARIO 2

{
    "moves": 0,
    "disks": 4,
    "targetTower": "C",
    "towers": {
        "A": [
            1,
            2,
            3,
            4
        ],
        "B": [],
        "C": []
    }
}

SCENARIO 3

{
    "moves": 0,
    "disks": 7,
    "targetTower": "Y",
    "towers": {
        "X": [],
        "Y": [],
        "Z": [
            1,
            2,
            3,
            4,
            5,
            6,
            7
        ]
    }
}

Explanation of the problem

Create a DataWeave script to solve the Tower of Hanoi puzzle. The input payload contains the number of moves (starting at 0), the total number of disks in the game, the target tower where all the disks have to be moved, and the 3 towers containing each disk.

(You can use this link to play the game online)

Here are the rules of the game:

• With each move, you can only move one disk at a time from its current stack to a different stack.

• You can only place smaller disks on top of bigger disks. For example, you can place disk 1 on top of disk 3 but you can't place disk 5 on top of disk 2.

• You can only move the disk at the top of any stack.

Expected output

For each of the three scenarios from the input, these are the expected outputs:

SCENARIO 1

{
  "moves": 7,
  "disks": 3,
  "targetTower": "C",
  "towers": {
    "A": [
      
    ],
    "B": [
      
    ],
    "C": [
      1,
      2,
      3
    ]
  }
}

SCENARIO 2

{
  "moves": 15,
  "disks": 4,
  "targetTower": "C",
  "towers": {
    "A": [
      
    ],
    "B": [
      
    ],
    "C": [
      1,
      2,
      3,
      4
    ]
  }
}

SCENARIO 3

{
  "moves": 127,
  "disks": 7,
  "targetTower": "Y",
  "towers": {
    "X": [
      
    ],
    "Y": [
      1,
      2,
      3,
      4,
      5,
      6,
      7
    ],
    "Z": [
      
    ]
  }
}

Clues

If you're stuck with your solution, feel free to check out some of these clues to give you ideas on how to solve it!

Clue #1

Clue #2

Clue #3

Clue #4

Answer

If you haven't solved this challenge yet, we encourage you to keep trying! It's ok if it's taking longer than you thought. We all have to start somewhere ✨ Check out the clues and read the docs before giving up. You got this!! 💙

There are many ways to solve this challenge, but you can find here my solution. I'm sure you all can make it better! :) Mine is super long 😂

Solution

I also recorded myself coming up with the solution, but without explanations. Just some lo-fi music and a screen :) you can leave the video in the background while working! :D let me know if you find this useful.

Feel free to comment your code below for others to see! 😄

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