Educational Codeforces Round 117 (Rated for Div. 2)

Solutions for Educational Codeforces Round 117 (Rated for Div. 2) (contest 1612). 5/7 problems verified against sample I/O. Difficulty range: 800-2800.

7 items

Educational Codeforces Round 117 (Rated for Div. 2)

Type: Div. 2 | Problems: 7 | Verified: 5/7 | Rating range: 800-2800 | Time: 12m 2s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Distance	800	brute-force, constructive-algorithms	1m 54s	✗
B	Special Permutation	900	constructive-algorithms, greedy	1m 36s	✗
C	Chat Ban	1300	binary-search, math	1m 15s	✓
D	X-Magic Pair	1600	math, number-theory	1m 7s	✓
E	Messages	2000	brute-force, dp, greedy	1m 25s	✓
F	Armor and Weapons	2800	brute-force, dp, greedy	3m 12s	✓
G	Max Sum Array	2500	combinatorics, constructive-algorithms, greedy	1m 33s	✓

Practice › Codeforces Solutions › Educational Codeforces Round 117 (Rated for Div. 2) ›

CF 1612F - Armor and Weapons

In this problem, Monocarp starts with the weakest armor and weapon, labeled 1. He can spend one hour to acquire a new armor set or weapon, but there is a catch: to obtain the $k$-th armor or weapon, he must already possess some armor and weapon combination whose total power is…

Practice › Codeforces Solutions › Educational Codeforces Round 117 (Rated for Div. 2) ›

CF 1612G - Max Sum Array

We are given a multiset of labels, where label i appears exactly ci times. We must arrange all these occurrences into a single array. Once the array is fixed, we look at every pair of identical values and add the distance between their positions.

Practice › Codeforces Solutions › Educational Codeforces Round 117 (Rated for Div. 2) ›

CF 1612E - Messages

We have a group of students, each of whom Monocarp wants to read a specific message in a chat. Every student has a limit on how many messages they will read in a day.

Practice › Codeforces Solutions › Educational Codeforces Round 117 (Rated for Div. 2) ›

CF 1612D - X-Magic Pair

We are given a pair of integers $a$ and $b$, and another integer $x$. We are allowed to repeatedly replace either $a$ or $b$ with the absolute difference $ The constraints allow $a, b, x$ to go up to $10^{18}$, and there can be up to $10^4$ test cases.

Practice › Codeforces Solutions › Educational Codeforces Round 117 (Rated for Div. 2) ›

CF 1612A - Distance

We are working on a grid where movement is measured using Manhattan distance, meaning the cost between two points is the sum of horizontal and vertical separations. One point is fixed at the origin, while the second point lies at coordinates $(x, y)$.

Practice › Codeforces Solutions › Educational Codeforces Round 117 (Rated for Div. 2) ›

CF 1612B - Special Permutation

We are asked to construct a permutation of numbers from 1 to n, where n is even. The permutation is split into two equal halves: the first n/2 elements form the left half, and the remaining n/2 elements form the right half. Two conditions must be satisfied simultaneously.

Practice › Codeforces Solutions › Educational Codeforces Round 117 (Rated for Div. 2) ›

CF 1612C - Chat Ban

We are asked to simulate a chat scenario where a user wants to send an "emote triangle" consisting of messages with increasing then decreasing numbers of emotes.