Is Clumsy Factorial easy or hard?

Clumsy Factorial is generally rated as a medium difficulty problem. The main challenge is correctly handling operator precedence while applying operations in a fixed repeating order. Once the stack simulation idea is clear, the implementation becomes straightforward.

Clumsy Factorial Python/Java solution

Python and Java implementations typically use a stack or list structure. Iterate from N to 1, apply operations in a repeating cycle, and update the stack accordingly. Python often uses a list as a stack, while Java implementations commonly use Stack or ArrayDeque.

How to solve Clumsy Factorial in O(n)?

Iterate from N down to 1 while cycling through the operations *, /, +, -. Use a stack to apply multiplication and division immediately to the top element, and push positive or negative numbers for addition and subtraction. After the loop, sum all stack elements to produce the final result. The iteration ensures linear O(n) time.

What is the best approach for Clumsy Factorial?

The stack-based simulation is the most reliable approach. It processes numbers from N to 1 while cycling through the operations *, /, +, and -. Multiplication and division are applied to the top of the stack, while addition and subtraction push new values. This method runs in O(n) time and O(n) space and closely mirrors how arithmetic expressions are evaluated.

Is Clumsy Factorial asked at Google/Amazon/Meta?

Clumsy Factorial represents a typical medium-level problem involving arithmetic simulation and stack usage. Variants of expression evaluation and stack-based operator handling appear in interviews at companies like Amazon, Google, and Meta, especially for mid-level algorithm rounds.

What data structure is used in Clumsy Factorial?

The most common solution uses a stack. The stack stores intermediate values so multiplication and division can be applied before addition and subtraction, preserving correct operator precedence during the simulation.

What is the time complexity of Clumsy Factorial?

Both common solutions run in O(n) time because each number from N down to 1 is processed once. The stack-based approach uses O(n) extra space to store intermediate values, while the optimized arithmetic approach reduces space complexity to O(1).

Description Solution Video 3:28

1006. Clumsy Factorial

Medium61.8% acceptance4 companies

The factorial of a positive integer n is the product of all positive integers less than or equal to n.

For example, factorial(10) = 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1.

We make a clumsy factorial using the integers in decreasing order by swapping out the multiply operations for a fixed rotation of operations with multiply '*', divide '/', add '+', and subtract '-' in this order.

For example, clumsy(10) = 10 * 9 / 8 + 7 - 6 * 5 / 4 + 3 - 2 * 1.

However, these operations are still applied using the usual order of operations of arithmetic. We do all multiplication and division steps before any addition or subtraction steps, and multiplication and division steps are processed left to right.

Additionally, the division that we use is floor division such that 10 * 9 / 8 = 90 / 8 = 11.

Given an integer n, return the clumsy factorial of n.

Example 1:

Input: n = 4
Output: 7
Explanation: 7 = 4 * 3 / 2 + 1

Example 2:

Input: n = 10
Output: 12
Explanation: 12 = 10 * 9 / 8 + 7 - 6 * 5 / 4 + 3 - 2 * 1

Constraints:

1 <= n <= 10⁴

Asked at 4 companies

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1006. Clumsy Factorial

Asked at 4 companies

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