How do you solve Truncate Sentence on LeetCode?

Truncate Sentence (LeetCode #1816) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(n) space complexity. Key insight: Understanding how to split strings is crucial.

What is the brute force solution for Truncate Sentence?

The brute force approach for Truncate Sentence is Brute Force, with O(n²) time complexity and O(1) space complexity. The brute force approach involves splitting the sentence into words and then manually constructing the truncated sentence by iterating through the words. This method is straightforward but inefficient for larger inputs. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Truncate Sentence?

Truncate Sentence uses the following concepts: Array, String. The recommended patterns to study are: Array, String.

What are the interview tips for Truncate Sentence?

Always clarify the problem constraints with the interviewer. Think about edge cases, such as very short sentences or large k values. Practice explaining your thought process while coding.

What are common mistakes when solving Truncate Sentence?

Not handling cases where k is greater than the number of words. Forgetting to trim spaces when constructing the final sentence.

#1816

Truncate Sentence

Easy

ArrayStringArrayString

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n²)	O(n)
Space	O(1)	O(n)

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Intuition

Time O(n)Space O(n)

The optimal approach efficiently splits the sentence into words and directly constructs the truncated sentence using slicing, which is faster and avoids unnecessary string concatenation.

⚙️

Algorithm

3 steps

1Step 1: Split the sentence into words using space as the delimiter.
2Step 2: Use slicing to get the first k words.
3Step 3: Join the sliced words back into a single string and return it.

solution.py4 lines

1s = 'Hello how are you Contestant'
2k = 4
3truncated = ' '.join(s.split()[:k])
4print(truncated)

ℹ

Complexity note: The time complexity is O(n) because we only traverse the string once to split it into words, and the space complexity is O(n) due to storing the words in an array.

1Understanding how to split strings is crucial.
2Slicing arrays can significantly optimize performance.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.