# Isomorphism of a Problem

What does finding the isomorphism to a popular coding problem mean?

Finding the isomorphism to a popular coding problem is essentially recognizing that the problem you are currently trying to solve is the same, or very similar, to a known problem, just disguised in a different way.

An isomorphism in computer science is an equivalence relation between two problems that preserves the structure of the problem. It means if you can map every instance of problem A to an instance of problem B such that the solutions to both instances yield the same result when transformed by the same mapping function, then A and B are isomorphic.

In simpler terms, if you can rewrite your problem in such a way that it becomes another well-known problem, then you have found an isomorphism.

Once you realize that your problem is isomorphic to a known problem, you can leverage existing algorithms and techniques that have already been developed for the known problem to solve your problem, often resulting in a much simpler and efficient solution.

For example, the longest common subsequence problem is isomorphic to the shortest edit distance problem. The maximum flow problem in a network is isomorphic to the bipartite matching problem. Recognizing these isomorphisms can often lead to significant time savings when developing solutions.

Is abstract representation of the problem the same as the isomorphic problem?

Not exactly, but they are closely related concepts.

The **abstract representation** of a problem is a version of the problem that strips away any real-world context or specific details, focusing only on the core structure of the problem. It’s about identifying the fundamental components of the problem such as the inputs, outputs, and the rules that govern the relationship between these inputs and outputs.

On the other hand, an **isomorphic problem** is a problem that, while it may appear different on the surface (perhaps due to being set in a different context or domain), has the same underlying structure as the original problem. This concept is about recognizing the similarity in problem structures across different contexts, which can help in applying known solutions from one problem to another.

So, while both abstract representation and problem isomorphism involve recognizing and focusing on the underlying structure of problems, they are not quite the same thing. Abstract representation is more about simplifying the problem to its essence, while isomorphism is about identifying equivalent problems across different contexts.

Will the problem and the isomorphic problem be represented by the same abstract representation of the problem?

Yes, generally speaking, a problem and its isomorphic counterpart would indeed share the same abstract representation. This is because an isomorphically equivalent problem shares the same underlying structure as the original problem, albeit often in a different context or domain.

The abstract representation is the distilled version of the problem, focusing on the core problem structure and removing specific real-world details. Since the problem and its isomorphic counterpart have the same core problem structure (which is what makes them isomorphic), their abstract representations would be the same.

However, it’s worth noting that the specific details and language used might differ between the original problem and its isomorph, reflecting their different contexts or domains. Nonetheless, the underlying abstract structure of the problem should remain consistent.

Will the problem and the isomorphic equivalent of the problem share the same visual model?

Yes, typically, a problem and its isomorphic counterpart would share the same visual model, as they have the same underlying structure. The visual model is used to represent the problem structure, which does not change between the problem and its isomorph.

However, the elements used in the visual representation might change to reflect the specific context of the isomorphic problem. For example, if the original problem uses time intervals and the isomorph uses physical intervals (like distances), the model will still be the same (showing overlaps, starts and ends) but the labels and specifics will change accordingly to reflect time versus distance.

So, while the specific elements in the visual representation might change, the overall structure and layout of the visual model, which illustrate the key relationships and principles in the problem, would remain the same.

The skill to find the isomorphic equivalent of a problem is called as what?

The ability to identify the isomorphic equivalent of a problem is often referred to as “problem isomorph identification” or “problem isomorph mapping”. This skill falls under the broader category of “abstract reasoning” or “abstract thinking”, which involves the ability to analyze information, detect patterns and relationships, and solve problems on a complex, thought-based level.

In the context of computer science and programming, it’s also a crucial aspect of “algorithmic thinking” – the ability to design new algorithms or modify existing ones for new applications. This skill is key to becoming a proficient problem solver, as it allows for the transfer and application of solutions from known problems to new, similar problems.

What can software engineers do to develop this skill?

Developing the skill of identifying isomorphic problems involves a combination of theoretical learning, practical application, and deliberate practice. Here are some strategies that can help software engineers develop this skill:

**Learn a variety of algorithms and data structures:**This is foundational knowledge for recognizing problem isomorphs. Each algorithm or data structure has certain types of problems for which it’s especially suited. By understanding a wide array, you’ll be better able to match a problem to a solution approach.**Solve a lot of problems:**The more problems you solve, the more familiar you’ll become with various problem structures. Websites like LeetCode, HackerRank, and CodeSignal offer many problems of varying difficulty that you can practice on.**Analyze solved problems:**Look at the solution for a problem and try to understand why that solution works. Try to understand the underlying principles or patterns the solution is based on. This will help you to recognize these principles when they appear in other problems.**Try to solve the same problem in different ways:**This can help you understand the problem structure better and can reveal isomorphs that weren’t initially apparent.**Discuss problems and solutions with others:**Participate in coding forums, study groups, or coding interview prep groups. Explaining your thought process to others can solidify your understanding, and hearing others explain their approaches can expose you to different ways of thinking.**Participate in competitive programming:**Competitive programming is a mind sport where participants try to solve well-defined problems by writing computer programs under specified limits. It is an excellent way to hone problem-solving skills, including recognizing problem isomorphs.**Think abstractly:**Try to remove the specific context of the problem and think about it in a more abstract way. What is the problem really about? What are you actually trying to achieve?

Becoming proficient at recognizing problem isomorphs will take time and practice. But with consistent effort, you can definitely improve this skill.

When we transform the original problem into an isomorphic one, we keep the structure of the problem but change its context. To show that our new problem works similarly to the original, we also translate the examples and constraints.

Here’s how it works:

**Examples**: The examples from the original problem are translated into the context of the new problem. In this case, the input numbers are considered as “ages,” and we get the same output when applying the same logic to them.- For example, in the original problem’s Example 1, nums = [1,4,3,7,4,5], k = 3. In the new problem, we consider the same numbers as ages, so ages = [1,4,3,7,4,5] and p = 3. We solve the problem using the same logic, hence the output remains 15.

**Constraints**: The constraints are transferred directly from the original problem to the isomorphic one. They don’t change because they define the boundaries of the problem’s input, which remain the same even though the context changes.- For example, “1 <= nums.length <= 105” from the original problem translates to “1 <= ages.length <= 105” in the new problem.

So, the examples and constraints from the original problem are translated directly into the context of the new problem to ensure they have the same structure and logic, even though the context has changed.