Dashboard · Exams · ZIO
Zonal Informatics Olympiad
IARCS Stage-1 informatics olympiad. Pen-and-paper paper on algorithmic problem-solving — no programming language knowledge required. 4 problems in 3 hours.
Updated 17 Aug 2026 ·Vacancy counts change every cycle — always confirm the exact number in the latest official notification before applying.
Sourced
Source: official exam authority notification · refreshed weekly. How this works →
Free ZIO preparation on Shishya
Take expert-curated mocks, practise previous year papers, and Ask Shishya when you're stuck — verified by students who cleared the same path. All free, no credit card. Sign in with Google to begin.
✦ Try a ZIO question — free, no signup
Measuring Algorithm EfficiencyA nested loop structure has the outer loop running n times and the inner loop running m times. What is the time complexity?
Tap an option to check your answer.
Start with a diagnostic
10 questions across the syllabus to see where you stand.
We are sourcing PYQs from the official notification PDFs. Coming soon.
Take any mock in your preferred language — use the language picker inside the mock to switch (Hindi, Telugu, Tamil, Bengali, and 15 more).
ZIO — Quick Practice
FULL20 questions · 180 min
Start mock →Full-length subject tests below — 25 questions each, real exam format, instant scoring. Want to drill a single topic? Every topic has its own 10-question test in the syllabus.
Algorithmic Problem Solving
20 QsTell Shishya exactly what to test you on — topics, size, difficulty — and get a fresh mock in seconds. Leave the box blank and we'll target your weakest topics.
Take a mock to see where you stand on the leaderboard.
Students
1
Mocks taken
2
Average score
85%
Top score
100%
What can I get from ZIO?
Mock-score → expected rank → likely outcome. Use the mocks below to find your current band, then plan how many marks you need to climb.
Elite tier — IOI potential
95–100% · Post-based exam (no numeric rank)
National camp probable
90–95% · Post-based exam (no numeric rank)
India participated at IOI-2026 held in Uzbekistan from August 9-16, 2026. The Indian team, selected through the ICO pathway (ZIO → INOI → IOITC), won two medals at the prestigious international competition.
IARCS has announced that registrations for ICO-2027 (including ZIO-2027) will open in October 2026. Details will be announced in the second half of September 2026.
At the Asia-Pacific Informatics Olympiad 2026 held online by Taiwan in May 2026, India won five medals. Samik Goyal won a gold medal, while Naman Singh, Mohammad Farhat, Arjun Tyagi and Avighna Chhatrapati won bronze medals.
Tap any topic for its study notes + a 10-question topic test
Introduction to Algorithms
What an algorithm is, step-wise problem decomposition, pseudocode reading.
Measuring Algorithm Efficiency
Time and space complexity intuition, big-picture growth rates without formal Big-O.
Searching
Linear search, binary search and variants over sorted/unsorted data.
Sorting
Selection, insertion, merge and quick sort intuition; stability and order properties.
Recursion
Recursive thinking, base/recursive cases, recursion tree, divide-and-conquer.
IOITC selection range
82–90% · Post-based exam (no numeric rank)
INOI strong contenders
70–82% · Post-based exam (no numeric rank)
INOI qualification range
55–70% · Post-based exam (no numeric rank)
Regional participation range
35–55% · Post-based exam (no numeric rank)
Below qualification threshold
0–35% · Post-based exam (no numeric rank)
AI-curated from historic cut-off patterns. Always verify with the latest official notification before making decisions.
ZIO-2026 registration deadline
passedThu, 30 Oct, 2025
Registration fee was Rs 472 (Rs 400 + GST)
ZIO-2026 admit card released
passedMon, 10 Nov, 2025
🏅ZIO-2026 exam (completed)
passedSat, 15 Nov, 2025
Exam held from 2 pm to 5 pm (3 hours)
ZIO-2026 result announced
passedThu, 18 Dec, 2025
Results announced in December 2025 as per schedule
🏅INOI-2026 exam (completed)
passedSat, 14 Feb, 2026
Second round for ZIO/ZCO qualifiers; C++ only
ICO-2027 notification (expected)
25 days awaySun, 20 Sept, 2026
Details will be announced in second half of September 2026
ZIO-2027 registration opens (expected)
36 days awayThu, 1 Oct, 2026
Registrations for ICO-2027 will open in October 2026
ZIO-2027 registration deadline (expected)
65 days awayFri, 30 Oct, 2026
Based on previous cycle pattern; typically late October
🏅ZIO-2027 exam (expected)
80 days awaySat, 14 Nov, 2026
Typically mid-November; ZIO-2026 was November 15, 2025
🏅INOI-2027 exam (expected)
171 days awaySat, 13 Feb, 2027
Typically mid-February; for ZIO-2027/ZCO-2027 qualifiers
Counting Principles
Sum and product rules, permutations, combinations applied to small enumerations.
Pigeonhole Principle
Existence arguments via pigeons/holes — colourings, residues, pairs.
Parity and Modular Reasoning
Even/odd reasoning, basic modular arithmetic for invariants.
Elementary Number Theory
Divisibility, gcd/lcm reasoning, prime factorisation puzzles.
Combinatorial Games
Winning/losing positions, Nim-like games, strategy stealing.
Sets and Logic
Inclusion-exclusion, propositional logic, truth tables in puzzles.
Constructive Problems
Building an explicit example/configuration that satisfies given rules.
Optimisation Puzzles
Finding minimum/maximum of a quantity under given constraints.
Scheduling and Ordering
Sequencing tasks, jobs or moves to satisfy precedence/deadline rules.
Grid and Geometry Puzzles
Reasoning on 2D grids — paths, colourings, tilings, distance puzzles.
Three Concrete Inputs Format
ZIO-style problems — solve three increasingly large concrete inputs by spotting an efficient method.
Central Sector Scholarship Scheme (CSSS)
₹12·Ministry of Education, Govt. of India