Truncate Sentence

Problem Description

You are given a sentence s and an integer k. You want to truncate s such that it contains only the first k words. Return s after truncating it.

Key Insights

• The input sentence consists of words separated by a single space.
• The task is to extract the first k words from the sentence.
• The constraints ensure that k will always be valid relative to the number of words in s.

Space and Time Complexity

Time Complexity: O(n), where n is the length of the string s since we may need to traverse the entire string to count the words.

Space Complexity: O(n), where n is the number of characters in the resulting truncated sentence (in the worst case, all characters are needed).

Solution

To solve the problem, we can:

1. Split the input string s into a list of words using space as a delimiter.
2. Slice the list to get the first k words.
3. Join the sliced list back into a string with spaces in between.

This approach uses an array to hold the words and simple string manipulation to construct the output.

Code Solutions