Split Message Based on Limit

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class Solution:
    def splitMessage(self, message: str, limit: int) -> List[str]:
        current_length = total_parts = index = 0

        while True:
            suffix_length = 3 + len(str(total_parts)) * 2
            if suffix_length >= limit:
                break

            required_length = current_length + len(message) + (3 + len(str(total_parts))) * total_parts
            if required_length <= limit * total_parts:
                break

            total_parts += 1
            current_length += len(str(total_parts))

        result_parts = []
        if 3 + len(str(total_parts)) * 2 < limit:
            for part_number in range(1, total_parts + 1):
                length_of_part = limit - (len(str(part_number)) + 3 + len(str(total_parts)))
                result_parts.append('%s<%s/%s>' % (message[index:index + length_of_part], part_number, total_parts))
                index += length_of_part

        return result_parts

10 Prerequisite LeetCode Problems

“Split Message Based on Limit” (LeetCode Problem #2468) involves string manipulation and the application of the greedy algorithm. Here are 10 problems to build these foundational skills:

“Length of Last Word” (LeetCode Problem #58): This problem introduces the basics of string manipulation, which is essential for the problem at hand.
“Reverse Words in a String III” (LeetCode Problem #557): This problem helps further improve your string manipulation skills.
“Split a String in Balanced Strings” (LeetCode Problem #1221): This problem requires you to split a string in a certain way, which is the fundamental concept of problem #2468.
“Partition Labels” (LeetCode Problem #763): This problem is a more advanced string splitting problem that requires you to consider the maximum partition size.
“License Key Formatting” (LeetCode Problem #482): This problem involves formatting a string with a specific length limit, which is similar to splitting a message based on a limit.
“Integer to English Words” (LeetCode Problem #273): This problem requires you to translate an integer into words, which requires breaking down a problem into smaller parts based on certain rules.
“Longest Substring with At Most K Distinct Characters” (LeetCode Problem #340): This problem introduces the concept of sliding window, which is helpful in many string manipulation problems.
“Text Justification” (LeetCode Problem #68): This problem involves splitting a text into lines with specific lengths, which is similar to problem #2468.
“Binary String With Substrings Representing 1 To N” (LeetCode Problem #1016): This problem requires manipulation of binary strings, which can provide additional practice with string manipulation.
“Reorganize String” (LeetCode Problem #767): This problem requires you to reorganize a string based on certain constraints, which can provide additional practice with greedy algorithms and string manipulation.

These cover string manipulation and greedy algorithm, which are essential for tackling the “Split Message Based on Limit” problem.

Problem Classification

Problem Statement: You are given a string, message, and a positive integer, limit.

You must split message into one or more parts based on limit. Each resulting part should have the suffix “<a/b>”, where “b” is to be replaced with the total number of parts and “a” is to be replaced with the index of the part, starting from 1 and going up to b. Additionally, the length of each resulting part (including its suffix) should be equal to limit, except for the last part whose length can be at most limit.

The resulting parts should be formed such that when their suffixes are removed and they are all concatenated in order, they should be equal to message. Also, the result should contain as few parts as possible.

Return the parts message would be split into as an array of strings. If it is impossible to split message as required, return an empty array.

Example 1:

Input: message = “this is really a very awesome message”, limit = 9 Output: [“thi<1/14>”,“s i<2/14>”,“s r<3/14>”,“eal<4/14>”,“ly <5/14>”,“a v<6/14>”,“ery<7/14>”," aw<8/14>",“eso<9/14>”,“me<10/14>”," m<11/14>",“es<12/14>”,“sa<13/14>”,“ge<14/14>”] Explanation: The first 9 parts take 3 characters each from the beginning of message. The next 5 parts take 2 characters each to finish splitting message. In this example, each part, including the last, has length 9. It can be shown it is not possible to split message into less than 14 parts. Example 2:

Input: message = “short message”, limit = 15 Output: [“short mess<1/2>”,“age<2/2>”] Explanation: Under the given constraints, the string can be split into two parts:

The first part comprises of the first 10 characters, and has a length 15.
The next part comprises of the last 3 characters, and has a length 8.

Constraints:

1 <= message.length <= 104 message consists only of lowercase English letters and ’ ‘. 1 <= limit <= 104

Analyze the provided problem statement. Categorize it based on its domain, ignoring ‘How’ it might be solved. Identify and list out the ‘What’ components. Based on these, further classify the problem. Explain your categorizations.

Visual Model of the Problem

How to visualize the problem statement for this problem?

Problem Restatement

Could you start by paraphrasing the problem statement in your own words? Try to distill the problem into its essential elements and make sure to clarify the requirements and constraints. This exercise should aid in understanding the problem better and aligning our thought process before jumping into solving it.

Abstract Representation of the Problem

Could you help me formulate an abstract representation of this problem?

Alternatively, if you’re working on a specific problem, you might ask something like:

Given this problem, how can we describe it in an abstract way that emphasizes the structure and key elements, without the specific real-world details?

Terminology

Are there any specialized terms, jargon, or technical concepts that are crucial to understanding this problem or solution? Could you define them and explain their role within the context of this problem?

Problem Simplification and Explanation

Could you please break down this problem into simpler terms? What are the key concepts involved and how do they interact? Can you also provide a metaphor or analogy to help me understand the problem better?

Constraints

Given the problem statement and the constraints provided, identify specific characteristics or conditions that can be exploited to our advantage in finding an efficient solution. Look for patterns or specific numerical ranges that could be useful in manipulating or interpreting the data.

What are the key insights from analyzing the constraints?

Case Analysis

Could you please provide additional examples or test cases that cover a wider range of the input space, including edge and boundary conditions? In doing so, could you also analyze each example to highlight different aspects of the problem, key constraints and potential pitfalls, as well as the reasoning behind the expected output for each case? This should help in generating key insights about the problem and ensuring the solution is robust and handles all possible scenarios.

Identification of Applicable Theoretical Concepts

Can you identify any mathematical or algorithmic concepts or properties that can be applied to simplify the problem or make it more manageable? Think about the nature of the operations or manipulations required by the problem statement. Are there existing theories, metrics, or methodologies in mathematics, computer science, or related fields that can be applied to calculate, measure, or perform these operations more effectively or efficiently?

Problem Breakdown and Solution Methodology

Given the problem statement, can you explain in detail how you would approach solving it? Please break down the process into smaller steps, illustrating how each step contributes to the overall solution. If applicable, consider using metaphors, analogies, or visual representations to make your explanation more intuitive. After explaining the process, can you also discuss how specific operations or changes in the problem’s parameters would affect the solution? Lastly, demonstrate the workings of your approach using one or more example cases.

Inference of Problem-Solving Approach from the Problem Statement

How did you infer from the problem statement that this problem can be solved using ?

Could you please provide a stepwise refinement of our approach to solving this problem?
How can we take the high-level solution approach and distill it into more granular, actionable steps?
Could you identify any parts of the problem that can be solved independently?
Are there any repeatable patterns within our solution?

Solution Approach and Analysis

Thought Process

Explain the thought process by thinking step by step to solve this problem from the problem statement and code the final solution. Write code in Python3. What are the cues in the problem statement? What direction does it suggest in the approach to the problem? Generate insights about the problem statement.

From Brute Force to Optimal Solution

Could you please begin by illustrating a brute force solution for this problem? After detailing and discussing the inefficiencies of the brute force approach, could you then guide us through the process of optimizing this solution? Please explain each step towards optimization, discussing the reasoning behind each decision made, and how it improves upon the previous solution. Also, could you show how these optimizations impact the time and space complexity of our solution?

Coding Constructs

Consider the following piece of complex software code.

What are the high-level problem-solving strategies or techniques being used by this code?
If you had to explain the purpose of this code to a non-programmer, what would you say?
Can you identify the logical elements or constructs used in this code, independent of any programming language?
Could you describe the algorithmic approach used by this code in plain English?
What are the key steps or operations this code is performing on the input data, and why?
Can you identify the algorithmic patterns or strategies used by this code, irrespective of the specific programming language syntax?

Language Agnostic Coding Drills

Your mission is to deconstruct this code into the smallest possible learning units, each corresponding to a separate coding concept. Consider these concepts as unique coding drills that can be individually implemented and later assembled into the final solution.

Dissect the code and identify each distinct concept it contains. Remember, this process should be language-agnostic and generally applicable to most modern programming languages.
Once you’ve identified these coding concepts or drills, list them out in order of increasing difficulty. Provide a brief description of each concept and why it is classified at its particular difficulty level.
Next, describe the problem-solving approach that would lead from the problem statement to the final solution. Think about how each of these coding drills contributes to the overall solution. Elucidate the step-by-step process involved in using these drills to solve the problem. Please refrain from writing any actual code; we’re focusing on understanding the process and strategy.

Targeted Drills in Python

Now that you’ve identified and ordered the coding concepts from a complex software code in the previous exercise, let’s focus on creating Python-based coding drills for each of those concepts.

Begin by writing a separate piece of Python code that encapsulates each identified concept. These individual drills should illustrate how to implement each concept in Python. Please ensure that these are suitable even for those with a basic understanding of Python.
In addition to the general concepts, identify and write coding drills for any problem-specific concepts that might be needed to create a solution. Describe why these drills are essential for our problem.
Once all drills have been coded, describe how these pieces can be integrated together in the right order to solve the initial problem. Each drill should contribute to building up to the final solution.

Remember, the goal is to not only to write these drills but also to ensure that they can be cohesively assembled into one comprehensive solution.