April Fools Day Contest 2013

6 problems from April Fools Day Contest 2013 (contest 290), difficulty 1400-2800. 6/6 solutions verified against sample I/O.

6 items

April Fools Day Contest 2013

April Fools | 6 problems | 6/6 verified | Difficulty 1400-2800 | 9m 4s

# Problem Rating Tags Accepted Time ✓
A Mysterious strings 1400 *special, implementation 3,236 1m 23s ✓
B QR code 1500 *special, implementation 2,616 1m 1s ✓
C WTF? 1700 *special, graph-matchings, implementation 1,672 2m 7s ✓
D Orange 1400 *special, implementation 1,904 2m 7s ✓
E HQ 2500 *special, constructive-algorithms 226 1m 18s ✓
F Greedy Petya 2800 *special, dfs-and-similar, graphs 153 1m 8s ✓
Practice › Codeforces Solutions › April Fools Day Contest 2013 ›

CF 290A - Mysterious strings

The entire task is a joke problem from the April Fools contest. The input is a single integer a between 1 and 40. Instead of computing anything, we must output a specific string associated with that position.
codeforces competitive-programming *special implementation Jun 5, 2026
Practice › Codeforces Solutions › April Fools Day Contest 2013 ›

CF 290C - WTF?

The input is not a conventional mathematical specification. Instead, it is a small program written in LOLCODE. The task is to determine what that program computes and print the resulting real number. The first input value is read into a variable that controls a loop.
codeforces competitive-programming *special graph-matchings implementation trees Jun 5, 2026
Practice › Codeforces Solutions › April Fools Day Contest 2013 ›

CF 290F - Greedy Petya

We are given an undirected graph with up to 20 vertices and up to 400 edges, and we need to decide whether there exists a simple path that visits every vertex exactly once.
codeforces competitive-programming *special dfs-and-similar graphs greedy Jun 5, 2026
Practice › Codeforces Solutions › April Fools Day Contest 2013 ›

CF 290E - HQ

We are given a single string made from a very small alphabet inspired by the HQ family of joke languages. The task is to decide whether this string is “valid” under the rules of the language HQ, and output either confirmation or rejection.
codeforces competitive-programming *special constructive-algorithms Jun 5, 2026
Practice › Codeforces Solutions › April Fools Day Contest 2013 ›

CF 290D - Orange

We are given a string consisting of English letters, both uppercase and lowercase, and an integer representing a "capitalization budget" between 0 and 26.
codeforces competitive-programming *special implementation Jun 5, 2026
Practice › Codeforces Solutions › April Fools Day Contest 2013 ›

CF 290B - QR code

The problem gives two small integers, each between 0 and 32 inclusive. You can think of them as describing how many unit squares are placed along two perpendicular directions of a grid-like construction.
codeforces competitive-programming *special implementation Jun 5, 2026