ZIO

Exam pattern

ZIO-2026 question paper, instructions to candidates: the paper carries 80 marks, broken up into four problems of 20 marks each. Each problem has three Test Cases; if all three are solved correctly the problem gets 20 marks, otherwise 5 marks for each Test Case solved correctly. All 4 x 3 = 12 Test Cases appear as separate Questions. All questions are compulsory (no optional questions), there are no negative marks, and all expected answers are integers. IARCS says the pattern is the same as in previous years and the paper is a computerized test on the TCS iON platform, worked out on paper with only the final answers typed in.

Read from: ZIO 2026 - Question paper, p. 1, 'Instructions to candidates' (items 1-5)

Syllabus

Official links and how they were checked

• Indian Computing Olympiad - IARCS Verified against the document
  Official website · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Opened https://www.iarcs.org.in/inoi/ on 2026-10-06 and read its text. It describes the Indian Computing Olympiad (organized annually by IARCS), Eligibility, Registration, Stages (ZIO, ZCO, INOI, IOITC), 'How to prepare for ICO', Incentives for students, Contact and Partners. Its 'How to prepare' section states: 'The syllabus for ZIO and ZCO is the list of Basic Topics in the Online Study Material' and 'The syllabus for INOI and IOITC is the IOI syllabus, given here' (link to https://ioinformatics.org/page/syllabus/12). Dates, registration details and incentives on the page are not copied.
• ICO Online Study Material - Topics (Basic topics and Advanced topics) Verified against the document
  Syllabus · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Opened https://www.iarcs.org.in/inoi/online-study-material/topics/ on 2026-10-06 and read its text. It lists 'Basic topics' (13 entries: Introduction, Efficiency, Searching, Sorting, Basic Graph Algorithms, Dynamic Programming, Greedy Algorithms, Computing Shortest Paths, Heaps, Permutations, Directed Acyclic Graphs, Computing Prefix Sums, Sliding Window Algorithms) and 'Advanced topics' (6 entries: Advanced Graph Algorithms, Dynamic Programming on Trees, Range Queries, Network Flows, Games and Strategies, Geometry). Every unit title in this file was compared back with that page text: each occurs in it, in the same order. Not compared: the 13 linked topic pages themselves were opened (HTTP 200) but carry only study notes and problems, not a syllabus, and are not copied.
• Indian Computing Olympiad - Archives (question papers and other material, 2002 onwards) Opened; part could not be confirmed
  Sample / previous-year papers · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Link to the official page, contents not read: opened https://www.iarcs.org.in/inoi/archives.php on 2026-10-06 (HTTP 200); it lists one archive page per year from 2002 to 2026 with question papers and other material. The papers themselves were not read and nothing in them is used as a source of the syllabus.
• Indian Computing Olympiad Archives 2026 (reports and ZIO-2026 paper) Opened; part could not be confirmed
  Sample / previous-year papers · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Link to the official page, contents not read as a source: opened https://www.iarcs.org.in/inoi/2026/ on 2026-10-06 (HTTP 200). It holds the reports on IOI, IOITC, EGOI, APIO, INOI, ZCO and ZIO of 2026 and links the ZIO-2026 question paper and solutions. Nothing on it is used as a source of the syllabus.
• Indian Computing Olympiad Archives 2025 (reports and ZIO-2025 paper) Opened; part could not be confirmed
  Sample / previous-year papers · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2025 · checked 6 Oct 2026
  Link to the official page, contents not read as a source: opened https://www.iarcs.org.in/inoi/2025/ on 2026-10-06 (HTTP 200). It holds the reports of 2025, links the ZIO-2025 question paper and solutions, and for ZCO-2025 and INOI-2025 links problems hosted on Codeforces (an outside site, not copied here). Nothing on it is used as a source of the syllabus.
• ZIO 2026 - Question paper Verified against the document
  Sample / previous-year papers · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Downloaded the 5-page PDF linked from https://www.iarcs.org.in/inoi/2026/ on 2026-10-06 (HTTP 200, application/pdf) and read its text layer: the page 'Instructions to candidates' and the four problems. The paper pattern recorded in this file was checked against that instruction page. The problems were not used as a source of syllabus topics.
• ZIO 2026 - Solutions Opened; part could not be confirmed
  Sample / previous-year papers · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Link to the official PDF, contents not read: listed on https://www.iarcs.org.in/inoi/2026/ (labelled by IARCS 'Solutions and cutoffs (PDF)'). Reachability was not separately checked beyond the listing. Nothing in it is used as a source of the syllabus.
• ZIO 2025 - Question paper Opened; part could not be confirmed
  Sample / previous-year papers · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2025 · checked 6 Oct 2026
  Link to the official PDF, contents not read: listed on https://www.iarcs.org.in/inoi/2025/. Nothing in it is used as a source of the syllabus.
• ZIO 2025 - Solutions Opened; part could not be confirmed
  Sample / previous-year papers · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2025 · checked 6 Oct 2026
  Link to the official PDF, contents not read: listed on https://www.iarcs.org.in/inoi/2025/ (labelled by IARCS 'Solutions and cutoffs (PDF)'). Nothing in it is used as a source of the syllabus.
• Indian Computing Olympiad - Current information (IARCS) Verified against the document
  Notices / FAQ · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Opened https://www.iarcs.org.in/inoi/current.php on 2026-10-06 and read its text. Its 'Exam details' for ZIO says the exam is administered as a computerized test on the TCS iON platform, the question paper pattern is the same as in previous years, solutions are worked out with pen and paper and only final answers are submitted, and 'The syllabus for ZIO is the list of Basic Topics in the ICO Online Study Material'. Dates, centres, registration and fee details on that page are not copied.
• ICO Online Study Material (training material and reading list) Verified against the document
  Prescribed / recommended reading (published by the body) · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Opened https://www.iarcs.org.in/inoi/online-study-material/ on 2026-10-06 and read its text. It is IARCS's self-study material for the Indian Computing Olympiad and lists reading material: Algorithm Design (Kleinberg, Tardos); Introduction to Algorithms (Cormen, Leiserson, Rivest, Stein); Algorithms (Dasgupta, Papadimitriou, Vazirani); Programming Challenges (Skiena, Revilla); Competitive Programming (Halim); Competitive Programmer's Handbook (Laaksonen); Start Competitive Programming! (Baharev, Zingaro); Algorithmic Thinking (Zingaro). It is study material and a book list, not a syllabus, and no chapter cites it.
• ICO Online Programming Contest and Online Judge (IARCS) Verified against the document
  Other official page · Indian Association for Research in Computing Science (IARCS) - Indian Computing Olympiad · 2026 · checked 6 Oct 2026
  Opened https://www.iarcs.org.in/inoi/programming-contest.php on 2026-10-06 and read its text: it points to the ICO Online Judge (archive of past IARCS online programming contest problems, where past problems can be submitted for instant feedback) and lists other practice resources. It is a practice resource, not a syllabus.