Is Length of Last Word easy or hard?

Length of Last Word is classified as an Easy problem on LeetCode with an acceptance rate of around 58%. The challenge mainly involves correctly handling trailing spaces and understanding basic string iteration.

Length of Last Word Python/Java solution

In Python or Java, the problem can be solved using either string splitting or reverse traversal. The split approach uses built-in functions like split() and trim(), while the optimal solution iterates from the end of the string and counts characters until a space appears.

How to solve Length of Last Word in O(n)?

Traverse the string from the end. First skip any trailing spaces, then count characters until a space or the beginning of the string is reached. This single pass guarantees O(n) time while using constant extra space.

What is the best approach for Length of Last Word?

The reverse traversal approach is usually the best solution. It scans the string from the end, skips trailing spaces, and counts characters of the last word. This method runs in O(n) time and O(1) space, making it more memory efficient than splitting the string.

Is Length of Last Word asked at Google/Amazon/Meta?

Length of Last Word appears frequently in coding interview preparation lists and has been reported in interview practice sets for companies like Amazon and Google. It tests basic string manipulation and edge-case handling such as trailing spaces.

What data structure is used in Length of Last Word?

The problem mainly uses string traversal rather than complex data structures. Some solutions temporarily use arrays created by splitting the string, but the optimal approach only relies on simple index pointers while scanning the string.

What is the time complexity of Length of Last Word?

The optimal solution runs in O(n) time where n is the length of the string. In the reverse traversal method, the algorithm scans the string once from right to left. Space complexity is O(1) because it only uses a few variables.

Description Solution Video 4:15

58. Length of Last Word

Easy59.7% acceptance7 companies

Given a string s consisting of words and spaces, return the length of the last word in the string.

A word is a maximal substring consisting of non-space characters only.

Example 1:

Input: s = "Hello World"
Output: 5
Explanation: The last word is "World" with length 5.

Example 2:

Input: s = "   fly me   to   the moon  "
Output: 4
Explanation: The last word is "moon" with length 4.

Example 3:

Input: s = "luffy is still joyboy"
Output: 6
Explanation: The last word is "joyboy" with length 6.

Constraints:

1 <= s.length <= 10⁴
s consists of only English letters and spaces ' '.
There will be at least one word in s.

Asked at 7 companies

Qualcomm

Google Bloomberg

TCS Amazon Microsoft Meta

Topics

String

4:15

Still stuck?Read 3 approaches, or watch a walkthrough.

Open solution

LanguageLoading editor…

1class Solution:
2    def lengthOfLastWord(self, s: str) -> int:
3        

Starter codePython 3Spaces: 4

Examples

Case 1Case 2Case 3

Input

"Hello World"

Input

"   fly me   to   the moon  "

Input

"luffy is still joyboy"

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