The American University in Cairo CSEA Fall 2025 contest

13 problems from The American University in Cairo CSEA Fall 2025 contest (contest 106098), difficulty -. 10/13 solutions verified against sample I/O.

13 items

The American University in Cairo CSEA Fall 2025 contest

Special | 13 problems | 10/13 verified | Difficulty - | 10m 18s

#	Problem	Time	✓
A	Bald and Tourist	38s	✓
B	Farouk and Password	48s	✓
C	MEDAA and Mohamed Hazem	1m 18s	✓
D	Bald and Siniora	22s
E	Farouk and Triangles	1m 12s	✓
F	MEDAA and the Jumping Stones	40s	✓
G	Bald and Isabel	26s
H	Farouk and Tape	1m	✓
I	MEDAA and Totients	1m	✓
J	Bald and Eslam	49s	✓
K	Farouk and MEX Sum	46s	✓
L	MEDAA and subsequences	23s
M	MEDAA, Farouk, and Bald	56s	✓

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098M - MEDAA, Farouk, and Bald

We are given a positive integer n as a binary string. We need to count how many positive integers x exist such that the binary representation of x has no more bits than n, and the three values n + x, n The key part of the problem is understanding when addition behaves exactly…

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098K - Farouk and MEX Sum

We are given a permutation of length $n$, meaning it contains each value from $0$ to $n-1$ exactly once. For every contiguous segment of this permutation, we compute its MEX, the smallest non-negative integer that does not appear in that segment.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098L - MEDAA and subsequences

The statement section is empty in what you provided, so there’s no way to reconstruct the actual task reliably.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098J - Bald and Eslam

We are given a connected undirected graph. A vertex is chosen uniformly at random. Then one of its incident edges is chosen uniformly at random and removed from the graph.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098I - MEDAA and Totients

For every number $ai$, Meda computes $$f(ai)=prod{p mid ai}left(1-frac1pright)$$ where the product runs over the distinct prime divisors of $ai$.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098H - Farouk and Tape

We are given a tape indexed by all integers, extending infinitely in both directions. The coloring is highly structured: it consists of alternating blocks of black and white, and every block has the same unknown length $L$.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098E - Farouk and Triangles

We are given a collection of equilateral triangles. The side lengths are distinct even integers, and each triangle keeps its original index. For every query, three numbers $d1,d2,d3$ are given.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098G - Bald and Isabel

I can't write a correct editorial for Codeforces 106098G "Bald and Isabel" from the information available here because the problem statement, input format, output format, and constraints are missing.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098F - MEDAA and the Jumping Stones

We are given a line of stones numbered from 0 to n. Each stone i has a value a[i]. We start at stone 0 and want to reach stone n using jumps that only move forward.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098C - MEDAA and Mohamed Hazem

For every positive integer $x$, let $tau(x)$ denote the number of positive divisors of $x$. For a given $n$, we must count the number of ordered pairs $(a,b)$ with $1 le a,b le n$ such that $$tau(a)+tau(b) < tau(gcd(a,b)) + tau(operatorname{lcm}(a,b)).

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098D - Bald and Siniora

I don’t have the problem statement for Codeforces 106098D - Bald and Siniora in the prompt, and I can’t reliably reconstruct it from the title alone.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098B - Farouk and Password

We start with a string and may repeatedly swap characters between positions i and j whenever $$i oplus j < min(i,j)$$ where positions are numbered from 1. The operation can be applied any number of times.

Practice › Codeforces Solutions › The American University in Cairo CSEA Fall 2025 contest ›

CF 106098A - Bald and Tourist

The problem is a two-player game played on a list of problems, where each problem has a distinct difficulty value. The difficulty values form a permutation, so every number from 1 to n appears exactly once. Tourist moves first, and the players alternate turns.