Factorial Using Recursion in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return 1 when n is 0.

DSA Typescript

function factorial(n: number): number {
  if (n === 0) {
    return [1];
  }
  return n * factorial(n - 1);
}

Drag options to blanks, or click blank then click option'

An

B0

C1

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Returning 0 instead of 1 for the base case.

Not handling the base case at all.

The factorial of 0 is defined as 1, so the function should return 1 when n is 0.

2fill in blank

medium

Complete the recursive call to calculate factorial of n-1.

DSA Typescript

function factorial(n: number): number {
  if (n === 0) {
    return 1;
  }
  return n * factorial([1]);
}

Drag options to blanks, or click blank then click option'

An - 1

Bn

Cn + 1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using n + 1 which causes infinite recursion.

Using n which does not reduce the problem.

The factorial function calls itself with n-1 to reduce the problem size until it reaches 0.

3fill in blank

hard

Fix the error in the base case condition to correctly check for n equals zero.

DSA Typescript

function factorial(n: number): number {
  if (n [1] 0) {
    return 1;
  }
  return n * factorial(n - 1);
}

Drag options to blanks, or click blank then click option'

A==

B===

C=

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using = which assigns instead of compares.

Using != which checks for inequality.

In TypeScript, use === to check for equality without type coercion.

4fill in blank

hard

Fill both blanks to create a recursive factorial function with a base case and recursive step.

DSA Typescript

function factorial([1]: number): number {
  if ([2] === 0) {
    return 1;
  }
  return [2] * factorial([2] - 1);
}

Drag options to blanks, or click blank then click option'

An

Bnum

Cx

Dval

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names causing reference errors.

Using undefined variables inside the function.

Using the same variable name 'n' for the parameter and inside the function keeps the code clear and consistent.

5fill in blank

hard

Fill all three blanks to create a recursive factorial function with parameter, base case check, and recursive call.

DSA Typescript

function factorial([1]: number): number {
  if ([2] === 0) {
    return 1;
  }
  return [3] * factorial([3] - 1);
}

Drag options to blanks, or click blank then click option'

Anum

Bn

Dval

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing variable names causing errors.

Forgetting to decrement the variable in recursive call.

Using 'n' consistently as the parameter and variable name ensures the function works correctly.