XXV Spain Olympiad in Informatics, Online Qualifier 1

6 problems from XXV Spain Olympiad in Informatics, Online Qualifier 1 (contest 105363), difficulty -. 3/6 solutions verified against sample I/O.

6 items

XXV Spain Olympiad in Informatics, Online Qualifier 1

Special | 6 problems | 3/6 verified | Difficulty - | 13m 27s

#	Problem	Time	✓
A	Hello!	1m 11s	✓
B	Closed by Subtraction	5m 9s
C	Squares in the Notebook	1m 59s	✓
D	Connecting Villages	1m 9s	✓
E	Beautiful Board	2m 13s
F	Coloring the Grid	1m 46s

Practice › Codeforces Solutions › XXV Spain Olympiad in Informatics, Online Qualifier 1 ›

CF 105363B - Closed by Subtraction

We are given several independent test cases. Each test case provides a finite set of distinct integers, and we need to decide whether this set satisfies a very specific structural property involving differences between elements.

Practice › Codeforces Solutions › XXV Spain Olympiad in Informatics, Online Qualifier 1 ›

CF 105363F - Coloring the Grid

We are given a geometric construction that can be reinterpreted as a graph problem. There are two families of segments.

Practice › Codeforces Solutions › XXV Spain Olympiad in Informatics, Online Qualifier 1 ›

CF 105363E - Beautiful Board

We are given a rectangular grid of $n times m$ cells, and we must assign each cell one of two colors. The coloring must satisfy two global conditions at the same time. First, exactly half of the cells must be black and the other half white.

Practice › Codeforces Solutions › XXV Spain Olympiad in Informatics, Online Qualifier 1 ›

CF 105363C - Squares in the Notebook

The page is drawn with a fixed set of horizontal guide lines, equally spaced one centimeter apart, and a set of vertical guide lines placed at arbitrary x-coordinates.

Practice › Codeforces Solutions › XXV Spain Olympiad in Informatics, Online Qualifier 1 ›

CF 105363D - Connecting Villages

We are given a network of villages connected by roads, where each road is initially unusable and becomes usable only after a certain number of hours. All roads “unlock” in parallel according to their own schedules. Once a road is unlocked, it can be used permanently.

Practice › Codeforces Solutions › XXV Spain Olympiad in Informatics, Online Qualifier 1 ›

CF 105363A - Hello!

We are given several short strings, and for each one we must decide whether it can be rearranged to form the word “hola”. Rearranging means we are allowed to permute the characters freely, but we cannot add or remove any character.