Computing & Informatics Olympiad Guide

In this context, informatics is not simply learning how computers work. Students are asked to take a problem and convert it into a computational solution.

A useful model is: Problem → Model → Algorithm → Code → Test → Optimise.

The British Informatics Olympiad is a national programming competition for school and college students.

Founded in 1995, BIO was established to encourage students to take an active interest in computing through challenging programming problems.

No. Knowing programming syntax is necessary, but it is only one part of successful competition performance.

A student who knows hundreds of programming commands may still struggle if they cannot design an effective algorithm.

Under the 2026 BIO rules, entrants had to be: Under 19 years old, Studying full-time, At a secondary or further-education institution rather than higher education, Based in mainland Britain.

Entries were coordinated through a member of staff at the student's school or college. Eligibility should always be checked against the rules for the current competition year.

No. BIO states explicitly that students do not need to be studying Computer Science to participate.

Some strong previous competitors have developed their programming skills independently. However, students still need sufficient practical programming ability to turn their ideas into working programs.

The BIO final is also used in selection for competitions including the European Girls' Olympiad in Informatics (EGOI) and the Western European Olympiad in Informatics (WEOI).

The 2026 first round consisted of 3 questions completed in 3 hours. The problems required programming solutions and were supplemented by written parts.

This means students needed to balance Programming, Mathematical Reasoning, Written Answers and Time Management.

For the 2026 first round, students could solve the programming tasks on any type of computer and in any programming language, according to the official competition rules.

This gives students flexibility to use a language they already understand well.

The best language for early preparation is usually one the student can use confidently. A suitable competition language should allow them to:

For beginners, clarity and fluency are more important than choosing a language simply because it appears advanced.

The 2026 BIO final rules stated that competitors would use computers running Linux and that C/C++ would be available as the programming language environment. Competitors were given an opportunity to familiarise themselves with the environment before the contest.

Therefore, students aiming for national-final progression should eventually become comfortable with the competition environment specified for their year.

For 2026, the best 15 competitors from Round One were invited to the final at Churchill College, Cambridge, alongside additional students competing for EGOI selection.

The final involved Programming Problems and Written Problems.

The top four selected competitors form the team representing Britain at the International Olympiad in Informatics (IOI).

The BIO final is also used to select or contribute to selection for EGOI and WEOI.

The International Olympiad in Informatics (IOI) is an international programming competition for high-performing pre-university students. Competitors tackle complex algorithmic problems using computers.

At BIO 2026, the four highest-selected finalists were due to form Britain's IOI team.

Successful students typically need a combination of:

This distinction is fundamental.

Algorithm = The Idea. Code = The Implementation of the Idea. Competition preparation must develop both.

and still struggle with informatics competitions.

Why? Because competition problems often ask: can you discover an efficient solution to a completely unfamiliar problem? — rather than: can you build something using familiar programming tools?

A strong mathematician may spot patterns and develop clever ideas but still need programming fluency. They must be able to convert: Reasoning → Algorithm → Working Program.

If implementation takes too long or introduces errors, a correct mathematical idea may not become a successful competition solution.

Before advanced algorithm work, students should be comfortable with:

These skills should become sufficiently automatic that they do not distract from problem solving.

Before writing code, identify:

Only then should implementation begin.

A common competition mistake is: Read First Paragraph → Start Typing.

Instead: Read → Understand → Model → Design → Then Code.

Five minutes of careful thinking can prevent 30 minutes of debugging the wrong approach.

Before implementing an algorithm, try small cases. If a problem allows values up to thousands or millions, test manually with 1, 2, 3 or Small Custom Inputs.

Small cases often expose the structure of the problem.

Some competition problems describe a process that can be modelled directly, for example: Move objects, Transform strings, Update positions, Follow instructions, Change states.

A simulation solution follows these rules computationally. Students should learn when direct simulation is sufficient — and when it becomes too slow.

Brute force means systematically trying many or all possibilities. It is sometimes Perfectly Acceptable and sometimes Far Too Slow.

Students need to ask: how many possibilities could there be? Before rejecting brute force, estimate its actual cost. Before using brute force, check whether it can finish within the required time.

Two programs can produce exactly the same answer but require dramatically different amounts of work. Suppose one method performs roughly n operations while another performs n².

For small inputs, both may work. For large inputs, the difference can become enormous. This is why competition programmers need to understand algorithmic efficiency.

Students should gradually learn concepts such as O(1), O(log n), O(n), O(n log n), O(n²) and more expensive growth rates.

The purpose is not simply to memorise notation. Students should be able to ask: will this algorithm remain practical for the maximum input size?

If a question says n ≤ 20, a very different algorithm may be possible compared with n ≤ 1,000,000.

Constraints are clues. They help students estimate which approaches might be intended. Always read them.

As students progress, they may need structures such as:

The goal is to understand: which structure makes the required operations efficient?

Arrays or lists are fundamental. Students should become comfortable with:

Strong array manipulation supports a large range of competition problems.

Students should recognise when repeated linear searching can be replaced with more efficient lookup.

Sorting is far more than a basic programming exercise. Once data is sorted, many problems become easier. Sorting can support:

Before inventing a complex method, ask: would sorting simplify the problem?

More advanced competitive programming also uses binary search on an answer space, not only on arrays.

Students should understand both how recursive calls work and when recursion becomes inefficient or unsafe.

Backtracking explores possible choices while abandoning paths that cannot produce a valid solution. A common structure is: Choose → Explore → Undo → Try Another Choice.

But students need to monitor how quickly the number of possibilities grows.

A greedy strategy repeatedly makes what appears to be the best immediate choice. This can produce an optimal solution for some problems — but fail badly for others.

Students therefore need to answer: why is this greedy choice always safe? A plausible idea is not enough.

Dynamic programming is useful when Subproblems Repeat and Previous Results Can Be Reused. Instead of repeatedly solving the same smaller problem, store its result.

A common development path is: Brute Force Recursion → Identify Repetition → Store Results → Dynamic Programming.

Many real and abstract problems can be modelled as Vertices + Edges. Examples include:

Students should learn to recognise when a problem is secretly a graph problem.

A queue is typically used to process states in increasing distance.

Depth-first search, or DFS, explores deeply before backtracking. It is useful for:

Students should understand both recursive and iterative implementations where appropriate.

As students advance, they may encounter weighted graph problems. These can require algorithms such as Dijkstra's Algorithm or other shortest-path techniques.

The key step is first recognising: this problem can be represented as a graph.

Strings appear frequently in programming competitions. Students should practise:

Strong string manipulation is especially valuable in early competition preparation.

Competitive programming often uses mathematical thinking. Useful areas can include:

Students do not necessarily need advanced school Mathematics for every problem, but mathematical maturity is highly valuable.

Modular arithmetic deals with remainders. For example: 17 mod 5 = 2, because dividing 17 by 5 leaves remainder 2.

These problems can often be approached either mathematically or algorithmically. Strong competitors learn to move between the two viewpoints.

A major competition skill is turning the story into something computational. A problem about People, Roads, Letters, Tiles or Games may really be about Graphs, Strings, Arrays, Dynamic Programming or Search.

Ask: what is the underlying structure?

A very fast wrong algorithm is still wrong. Preparation should follow: Understand → Build Correct Solution → Test → Then Optimise.

Students should avoid premature optimisation before they are certain what problem they are solving.

Programs often work on typical examples but fail at boundaries. Always test cases such as:

The specific cases depend on the problem.

Passing the sample input only proves your program works on the sample input. It does not prove that the algorithm is correct.

Create additional tests. Ask: what situation might break my assumptions?

When a program fails:

Randomly changing code is inefficient.

Sometimes the problem is not the code.

Before rewriting code, reread the problem statement.

The 2026 BIO marking scheme shows that competition programs were black-box tested using specified test data. Programs had to produce correct outputs, and relevant tests were required to terminate within one second to receive marks.

This demonstrates why both Correctness and Efficiency matter.

BIO Round One is not purely about submitting code. The official structure includes Programming Tasks and Written Problems.

Students should therefore practise explaining reasoning and calculating results without depending entirely on running code.

The official 2026 marking instructions encouraged competitors to read the questions before attempting their answers.

rather than automatically beginning with Question 1.

A competition problem may have several parts or test groups. Students should not assume “If I cannot solve the whole problem, there is no point attempting it.”

A simpler or less efficient solution may still solve some cases. Understanding how to secure partial progress can be valuable in programming competitions.

Instead of trying to implement the perfect algorithm immediately:

This reduces the risk of spending most of the competition implementing an advanced idea that never works.

The BIO website maintains historical Competition Papers, Programming Problems and Mark Schemes for students and schools. The 2026 Round One page, for example, publishes both the paper and mark scheme after the competition.

These are valuable because they show authentic competition-style problems.

Avoid: Read Problem → Read Solution → Move On.

Use:

Students can track: Problem, Main Idea, What Went Wrong?, Key Learning, Reattempt — for example: 1. Simulation — Misread rule — Model states first — Yes; 2. Strings — Too many loops — Improve lookup — Yes; 3. Graph — Missed BFS — Model moves as edges — Yes; 4. DP — Recalculated states — Store previous results — Yes; 5. Greedy — No proof — Test counterexamples — Yes.

This helps convert individual problems into reusable knowledge.

This classification helps students practise more intelligently.

After understanding a solution, close the notes. Wait several days. Then attempt the problem again.

A student who can reconstruct the algorithm independently has learned significantly more than one who merely recognises the official solution.

Memorising entire solutions is weak preparation. Students should understand reusable ideas such as BFS, Binary Search, Dynamic Programming, Sorting, Frequency Counting but must still adapt them to new problems.

The objective is: recognise the pattern → adapt the algorithm, not copy a remembered program.

AI can be useful outside formal competition settings for explaining concepts or reviewing learning when used responsibly. However, competition rules must always be followed.

For BIO 2026, the official marking instructions explicitly stated that students could not use AI code-generation tools during the contest. Internet use was also restricted, apart from online help required for the student's programming language.

Students should therefore practise solving and implementing problems independently.

A student preparing for BIO should be able to:

without relying on generated code. That independence is a core competition skill.

A beginner should not immediately start with national-final problems.

Use: Programming Basics → Short Logic Problems → Simple Simulations → Search & Sorting Problems → Algorithmic Problems → Past BIO Questions → Advanced Olympiad Problems.

Difficulty should increase gradually.

At higher levels, programming syntax should no longer be the main obstacle.

Students aiming beyond Round One should prepare for a major increase in difficulty.

The 2026 final was held at Churchill College, Cambridge, with competitors using a Linux-based environment and C/C++ expected to be available.

Students do not need to abandon another programming language immediately simply because C++ is common in advanced competitive programming.

A sensible progression is: Learn Problem Solving First, then, when needed, Develop C++ Fluency.

This is an example and should be adjusted to the student's experience.

There is no universal number of hours.

Quality matters more than simply accumulating coding time.

The strongest indicator is not memorising more code. It is solving increasingly unfamiliar problems independently.

That is normal. Competition programming is deliberately difficult.

Struggling productively is part of learning.

After reviewing a solution, ask:

A solution should teach a strategy — not merely provide code.

Parents do not need to be programmers.

A useful question is “What algorithm did you try, and why?” rather than only “Did your program work?”

What is the British Informatics Olympiad?

The BIO is the national computing competition for schools and colleges in Britain, focused on solving programming problems under competition conditions.

Who can enter BIO?

For BIO 2026, entrants had to be under 19 and studying full-time in secondary or further, rather than higher, education in mainland Britain. Current-year eligibility should always be checked.

Do students need to study Computer Science?

No. BIO states that students do not need to be studying Computer Science, and some successful competitors have been self-taught.

How long is the first round?

The 2026 first round lasted three hours and consisted of three main questions.

Which programming language can students use?

For BIO 2026 Round One, students could use any programming language on any type of computer.

Is BIO only about coding?

No. It assesses algorithmic problem solving, programming, efficiency and written reasoning.

How many students reach the BIO final?

Under the 2026 rules, the best 15 first-round competitors were invited, alongside additional competitors involved in EGOI selection.

Where was the 2026 final held?

The 2026 final took place at Churchill College, Cambridge.

Can BIO lead to the International Olympiad in Informatics?

Yes. Four selected finalists form Britain's team for the IOI under the BIO pathway.

Are past BIO papers available?

Yes. The BIO website maintains historical competition questions and publishes papers and mark schemes, including the 2026 Round One materials.