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213 tasks across the Municipal, Regional, and National rounds (2009–2026), plus 4 previously featured problems. 146 tasks have independently written English summaries, analyses, and C++17 solutions; the remaining entries link to Arena. Topic tags are from Arena or our reviewed explanations. Difficulty labels are learning estimates, not official ratings.

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RoundYearContent

Graphs38

BFS & shortest paths 8

BFS with state masks 1

Connected Components 1

Cycle detection 1

Cycle Equations 1

DFS & reachability 5

Dijkstra & weighted routes 7

Directed Bfs 1

DSU & connectivity 2

Grid Distance 1

Lowest common ancestor 1

Minimum spanning trees 1

Multi Source Bfs 1

Permutation cycles & weighted swaps 1

Spanning trees 1

Strongly Connected Components 1

Topological Order 1

Trees & DAGs 3

Dynamic Programming42

Acyclic State Dp 1

Bitmask Dp 1

Combinatorial Dp 2

Combinatorial DP 1

Counting Dp 1

Digit Dp 1

Dynamic programming 14

Dynamic programming on grids 1

Interval Dp 3

Interval dynamic programming 1

Knapsack 1

Layered Dp 1

Linear Dp 3

Multiple Pointer Generation 1

Ordered States 1

Polynomial Dp 1

Sequence Dp 1

Sliding Window Dp 1

String Segmentation 1

Subsequence Counting 1

Subset Dp 1

Subset Sum 2

Unbounded Knapsack 1

Greedy Algorithms14

Coverage 1

Digit Construction 1

Enumeration And Packing 1

Greedy algorithms 3

Greedy digit construction 1

Greedy selection & counting 1

Interval Costs 1

Interval Expansion 1

Monotonic Stack 1

Permutations 1

Sorting And Binary Search 1

Sorting Greedy 1

Arrays & Sorting20

Distance Transform 1

Frequency Counting 1

Interval Merging 2

Matrices & grids 1

Matrix Traversal 2

Prefix Sums 2

Reverse Difference Arrays 1

Run Length Counting 1

Sorting 1

Sweep Line 2

Two pointers & sliding windows 6

Search & Enumeration11

Backtracking 2

Binary search 1

Binary Search 1

Binary Search Answer 2

Binary Search On Answer 1

Binary search on the answer 2

Enumeration & brute force 2

Strings9

Coordinate Compression 1

Hashing 1

Implicit Strings 1

Overlap 1

Palindromes 1

Prefix Function 1

Prefix Sums 1

Strings 1

Subsequence recognition 1

Mathematics37

Big integers 1

Big Integers 2

Binary Representation 1

Binomial Coefficients 1

Bitwise Xor 1

Combinatorial unranking 1

Combinatorics 3

Compressed Gcd States 1

Digit arithmetic 1

Digit Counting 1

Divisibility 1

Divisors 3

Extended Euclid 1

Fractions 1

Gcd And Divisors 1

Information bounds & binary codes 1

Integer Powers 1

Invariants 1

Mathematics 2

Modular Arithmetic 1

Number theory 1

Numeral Systems 1

Prefix Formulas 1

Prime Factorization 1

Prime factors & sliding windows 1

Prime Sieve 3

Rational Arithmetic 1

Recurrences 1

Sum Identities 1

Geometry8

Angles 1

Circular Intervals 1

Coordinate Geometry 1

Intervals 1

Polygon Clipping 1

Sorting Faces 1

Sweep Line 2

Data Structures8

Monotonic Queue 1

Ordered Sets 1

Sets 1

Stacks & expressions 5

Implementation8

Bit manipulation & decoding 1

Counting 1

Grid Simulation 1

Interpreters & memoization 1

Ranked Choice Simulation 1

Simulation 3

Topic Not Yet Reviewed22

Awaiting topic review 22

Try the problem yourself before reading the analysis. Every solution uses standard C++17 headers.

GROUP C2026 · Not assessedAwaiting topic review

cak

National Olympiad — National round

Submission name: cak.cpp

Source catalogue entry

This task is indexed from Arena’s Group C Olympiad archive. An English explanation and verified C++17 solution have not been added yet.

Arena supplies no recognized algorithm tags for this entry. Its topic and difficulty still need review.

Use the source link below to open the official problem.

Source: Arena Olimpiici ↗

Real problems.Your next challenge.

cak

Source catalogue entry

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Real problems.
Your next challenge.