Leetcode #2788: Split Strings by Separator

In this guide, we solve Leetcode #2788 Split Strings by Separator in Python and focus on the core idea that makes the solution efficient.

You will see the intuition, the step-by-step method, and a clean Python implementation you can use in interviews.

Problem Statement

Given an array of strings words and a character separator, split each string in words by separator. Return an array of strings containing the new strings formed after the splits, excluding empty strings.

Quick Facts

• Difficulty: Easy
• Premium: No
• Tags: Array, String

Intuition

We need to scan characters while tracking positions or counts.

A simple state machine keeps the logic precise.

Approach

Iterate through the string once and update the state for each character.

Use a map or array if you need fast lookups.

Steps:

• Iterate through characters.
• Maintain necessary state.
• Build or validate the output.

Example

Python Solution

Complexity

The time complexity is $O(n \times m)$, and the space complexity is $O(m)$, where $n$ is the length of the string array $words$, and $m$ is the maximum length of the strings in the array $words$. The space complexity is $O(m)$, where $n$ is the length of the string array $words$, and $m$ is the maximum length of the strings in the array $words$.

Edge Cases and Pitfalls

Watch for boundary values, empty inputs, and duplicate values where applicable. If the problem involves ordering or constraints, confirm the invariant is preserved at every step.

Summary

This Python solution focuses on the essential structure of the problem and keeps the implementation interview-friendly while meeting the constraints.