April Fools Day Contest 2026

10 problems from April Fools Day Contest 2026 (contest 2214), difficulty -. 5/10 solutions verified against sample I/O.

10 items

April Fools Day Contest 2026

April Fools | 10 problems | 5/10 verified | Difficulty - | 18m 14s

#	Problem	Tags	Accepted	Time	✓
A	Odd One Out	*special, graph-matchings, implementation	10,114	1m 7s	✓
B	Are You Smiling?	*special, strings	6,549	1m 10s	✓
C	And?	*special, bitmasks	1,814	7m 7s
D	Neural Feud	*special, strings	4,264	1m 29s
E	Shortest Paths	*special, shortest-paths	1,046	1m 10s	✓
F	Numbers	*special	934	33s
G	Anomaly	*special, communication	719	1m 34s
H	Double Vision	*special	1,599	1m 30s
I	You Are a Robot	*special	296	1m 36s	✓
J	Special Problem	*special, brute-force, games	3,537	58s	✓

Practice › Codeforces Solutions › April Fools Day Contest 2026 ›

CF 2214C - And?

In this problem, we are given three integers for each test case, which we can call a, b, and c. The task is to compute a single integer for each test case based on a bitwise operation involving these numbers.

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CF 2214I - You Are a Robot

We are given a tree rooted at node 1, where each edge connects a parent to a child and is marked as either empty (0), contains a human (1), or contains a robot (2). A trolley starts at the root and moves along the tree.

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CF 2214J - Special Problem

This problem presents an interactive game scenario where you have a hidden system generating some responses. The goal is to query the system in a structured way to deduce a hidden value or sequence.

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CF 2214H - Double Vision

This is a visual reasoning problem where the input describes a picture rather than a traditional numeric structure. You are given a grid-like arrangement of cells that visually encode information in two overlapping interpretations.

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CF 2214G - Anomaly

The problem presents a hidden string of length 11, and our task is to report the character at a given 1-based index for multiple queries. Each query consists of a single integer, and the output is simply the character at that position in the string.

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CF 2214F - Numbers

Before I start, can you clarify if the problem "Codeforces 2214F - Numbers" has multiple test cases per input, or is it guaranteed to be a single instance per run? This affects the structure of the Python solution.

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CF 2214D - Neural Feud

The problem gives a very simple interaction: there are eight pre-defined questions, each associated with a single-word answer. You receive an integer n between 1 and 8, indicating which question is being asked, and you must output the corresponding answer.

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CF 2214E - Shortest Paths

We are given a weighted undirected graph with up to a hundred vertices. Each edge connects two numbered nodes and has a non-negative cost.

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CF 2214B - Are You Smiling?

The task is phrased in an intentionally playful way, but the underlying requirement is straightforward string reconstruction under a fixed pattern constraint. We are given a single input line containing a sentence.

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CF 2214A - Odd One Out

In this problem, we are presented with a set of four tiles, each labeled by a combination of a letter and a digit. Three of the tiles are identical, and one differs in either the letter or the digit. Our goal is to identify this "odd one out" and print its label.