Codeforces Round 563 (Div. 2)

Solutions for Codeforces Round 563 (Div. 2) (contest 1174). 3/6 problems verified against sample I/O. Difficulty range: 1000-2500.

6 items

Codeforces Round 563 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 3/6 | Rating range: 1000-2500 | Time: 24m 56s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Ehab Fails to Be Thanos	1000	constructive-algorithms, greedy, sortings	2m 41s	✗
B	Ehab Is an Odd Person	1200	sortings	1m 33s	✓
C	Ehab and a Special Coloring Problem	1300	constructive-algorithms, number-theory	2m 22s	✓
D	Ehab and the Expected XOR Problem	1900	bitmasks, constructive-algorithms	5m 12s	✗
E	Ehab and the Expected GCD Problem	2500	combinatorics, dp, math	1m 17s	✓
F	Ehab and the Big Finale	2400	constructive-algorithms, divide-and-conquer, graphs	11m 51s	✗

Practice › Codeforces Solutions › Codeforces Round 563 (Div. 2) ›

CF 1174F - Ehab and the Big Finale

We are given a tree with nodes numbered from 1 to n, rooted at node 1. Inside this tree, there is a hidden node x.

Practice › Codeforces Solutions › Codeforces Round 563 (Div. 2) ›

CF 1174D - Ehab and the Expected XOR Problem

We are asked to build a sequence of integers, each lying in the range from 1 up to $2^n - 1$, with a very specific restriction on its contiguous segments.

Practice › Codeforces Solutions › Codeforces Round 563 (Div. 2) ›

CF 1174A - Ehab Fails to Be Thanos

We are given a multiset of integers of size exactly twice some number n. The task is to rearrange these values into a new order such that if we split the reordered array into two consecutive halves of length n, the sum of the left half is different from the sum of the right half.

Practice › Codeforces Solutions › Codeforces Round 563 (Div. 2) ›

CF 1174C - Ehab and a Special Coloring Problem

We are asked to assign a label to every integer from 2 up to n. These labels are positive integers, and they must satisfy a strong interaction rule: whenever two numbers share no common divisor greater than 1, meaning they are coprime, their assigned labels must be different.

Practice › Codeforces Solutions › Codeforces Round 563 (Div. 2) ›

CF 1174E - Ehab and the Expected GCD Problem

We are asked to consider all permutations of the numbers from 1 to $n$. For each permutation, we define a sequence of prefix greatest common divisors (GCDs). Specifically, for the permutation $p = [p1, p2, ..., pn]$, we calculate $gi = gcd(p1, p2, ..., pi)$ for $i$ from 1 to $n$.

Practice › Codeforces Solutions › Codeforces Round 563 (Div. 2) ›

CF 1174B - Ehab Is an Odd Person

We are given a sequence of numbers, and we are allowed to reorder it, but with a restriction on how swaps work. A swap is only legal if we pick two positions whose values have opposite parity, meaning one is odd and the other is even.