How do you solve Sentence Similarity III on LeetCode?

Sentence Similarity III (LeetCode #1813) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(1) space complexity. Key insight: Identify common prefixes and suffixes to determine similarity.

What is the brute force solution for Sentence Similarity III?

The brute force approach for Sentence Similarity III is Brute Force, with O(n²) time complexity and O(1) space complexity. The brute force approach checks all possible ways to insert words from one sentence into another. It involves comparing all prefixes and suffixes of both sentences to see if they can be made equal. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Sentence Similarity III?

Sentence Similarity III uses the following concepts: Array, Two Pointers, String. The recommended patterns to study are: Two Pointers, String Manipulation.

What are the interview tips for Sentence Similarity III?

Clarify the problem statement and constraints before jumping into coding. Think aloud to demonstrate your thought process. Test your solution with various examples, especially edge cases.

What are common mistakes when solving Sentence Similarity III?

Not considering edge cases like empty sentences. Overlooking the need for spaces when inserting words.

#1813

Sentence Similarity III

Medium

ArrayTwo PointersStringTwo PointersString Manipulation

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

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

💡

Intuition

Time O(n)Space O(1)

The optimal solution identifies the longest common prefix and suffix between the two sentences. If the remaining parts of the sentences after removing these parts are empty or can be matched, then the sentences are similar.

⚙️

Algorithm

4 steps

1Step 1: Split both sentences into lists of words.
2Step 2: Identify the longest common prefix by comparing words from the start.
3Step 3: Identify the longest common suffix by comparing words from the end.
4Step 4: Check if the remaining parts of both sentences can be made equal.

solution.py12 lines

1def areSentencesSimilar(sentence1, sentence2):
2    words1 = sentence1.split()
3    words2 = sentence2.split()
4    n1, n2 = len(words1), len(words2)
5    i, j = 0, 0
6    while i < n1 and j < n2 and words1[i] == words2[j]:
7        i += 1
8        j += 1
9    while i < n1 and j < n2 and words1[n1 - 1 - (i - j)] == words2[n2 - 1 - (j - i)]:
10        i += 1
11        j += 1
12    return i + j == n1 + n2

ℹ

Complexity note: This complexity is efficient because we only traverse each sentence a limited number of times, specifically for prefix and suffix checks.

1Identify common prefixes and suffixes to determine similarity.
2Understanding how to manipulate strings can simplify complex problems.

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