Generate All Permutations of Array in DSA Typescript - Build from Scratch

Generate All Permutations of Array

📖 Scenario: You are working on a puzzle game where you need to find all possible ways to arrange a set of unique numbers. This helps the game engine explore every possible move.

🎯 Goal: Build a TypeScript program that generates all permutations of a given array of numbers.

📋 What You'll Learn

Create an array called numbers with the exact values [1, 2, 3].

Create a variable called result to store all permutations as arrays.

Write a recursive function called permute that generates all permutations of numbers.

Print the result array showing all permutations.

💡 Why This Matters

🌍 Real World

Generating all permutations is useful in games, puzzles, and testing all possible arrangements in scheduling or routing problems.

💼 Career

Understanding permutations and recursion is important for software engineers working on algorithms, optimization, and problem-solving tasks.

1

Create the initial array

Create an array called numbers with the exact values [1, 2, 3].

DSA Typescript

# Your code here

Hint

Use const numbers = [1, 2, 3]; to create the array.

2

Create a result array to store permutations

Create a variable called result and set it to an empty array to store all permutations.

DSA Typescript

const numbers = [1, 2, 3];
// Your code here

Hint

Use const result: number[][] = []; to create an empty array for storing permutations.

3

Write the recursive permutation function

Write a recursive function called permute that takes two parameters: arr (array of numbers) and temp (array for current permutation). The function should generate all permutations of numbers and store them in result. Use permute(numbers, []) to start.

DSA Typescript

const numbers = [1, 2, 3];
const result: number[][] = [];

// Your code here

Hint

Use recursion to build permutations by adding numbers not yet in temp. When temp length equals arr length, add a copy of temp to result.

4

Print all permutations

Write a console.log(result) statement to print all generated permutations stored in result.

DSA Typescript

const numbers = [1, 2, 3];
const result: number[][] = [];

function permute(arr: number[], temp: number[]) {
    if (temp.length === arr.length) {
        result.push([...temp]);
        return;
    }
    for (let i = 0; i < arr.length; i++) {
        if (temp.includes(arr[i])) continue;
        temp.push(arr[i]);
        permute(arr, temp);
        temp.pop();
    }
}

permute(numbers, []);

// Your code here

Hint

Use console.log(result) to display all permutations.