Is Array Prototype Last easy or hard?

Array Prototype Last is classified as an Easy problem. The main concept is handling the empty array edge case and retrieving the final element using constant-time array indexing.

Array Prototype Last Python/Java solution

In Python or Java, implement a helper function that returns -1 if the array or list is empty; otherwise return arr[len(arr) - 1] in Python or arr[n - 1] in Java. Both implementations run in O(1) time and O(1) space.

How to solve Array Prototype Last in O(1)?

Use direct index access. If the array is empty, return -1. Otherwise return the element at index n - 1 where n is the array length. This avoids loops and keeps the solution constant time.

What is the best approach for Array Prototype Last?

The best approach is direct index access. Check if the array length is zero and return -1; otherwise return the element at index length - 1. This works in O(1) time and O(1) space since array indexing is constant time.

Is Array Prototype Last asked at Google/Amazon/Meta?

Array Prototype Last is a basic array manipulation problem commonly used in coding platforms to test understanding of language features and edge cases. While simpler than typical FAANG interview questions, similar array boundary problems appear in early screening rounds.

What data structure is used in Array Prototype Last?

The problem uses a standard array data structure. The solution relies on constant-time random access provided by arrays to retrieve the last element using index length - 1.

What is the time complexity of Array Prototype Last?

The time complexity is O(1). The algorithm performs only a length check and a single array index lookup, both constant-time operations. No iteration or additional processing is required.

Description Hints 2 Solution Video 6:17

2619. Array Prototype Last

Easy74.0% acceptance5 companies

Write code that enhances all arrays such that you can call the array.last() method on any array and it will return the last element. If there are no elements in the array, it should return -1.

You may assume the array is the output of JSON.parse.

Example 1:

Input: nums = [null, {}, 3]
Output: 3
Explanation: Calling nums.last() should return the last element: 3.

Example 2:

Input: nums = []
Output: -1
Explanation: Because there are no elements, return -1.

Constraints:

arr is a valid JSON array
0 <= arr.length <= 1000

Asked at 5 companies

Google Bloomberg Amazon Microsoft Meta

Hints open one at a time

Hint 1

Inside the Array.prototype.last function body, you have access to the "this" keyword. "this" is equal to the contents of the array in this case.

Hint 2

You can access elements in the array via this[0], this[1], etc. You can also access properties and method like this.length, this.forEach, etc.

6:17

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2619. Array Prototype Last

Asked at 5 companies

Hints open one at a time

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