Codeforces Round 1034 (Div. 3)

7 problems from Codeforces Round 1034 (Div. 3) (contest 2123), difficulty 800-2100. 2/7 solutions verified against sample I/O.

7 items

Codeforces Round 1034 (Div. 3)

Div. 3 | 7 problems | 2/7 verified | Difficulty 800-2100 | 12m 37s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Blackboard Game	800	math	41,674	1m 37s	✓
B	Tournament	800	greedy	34,895	1m 44s	✓
C	Prefix Min and Suffix Max	1000	brute-force, data-structures	30,865	1m 35s
D	Binary String Battle	1200	constructive-algorithms, games, greedy	21,881	1m 28s
E	MEX Count	1400	binary-search, data-structures, greedy	14,894	1m 24s
F	Minimize Fixed Points	1700	constructive-algorithms, number-theory	9,755	3m 13s
G	Modular Sorting	2100	brute-force, data-structures, greedy	3,247	1m 36s

Practice › Codeforces Solutions › Codeforces Round 1034 (Div. 3) ›

CF 2123F - Minimize Fixed Points

We are asked to construct a permutation of integers from $1$ to $n$ such that for every position $i$ from $2$ to $n$, the greatest common divisor of the position and its value, $gcd(pi, i)$, is strictly greater than $1$.

Practice › Codeforces Solutions › Codeforces Round 1034 (Div. 3) ›

CF 2123G - Modular Sorting

We are maintaining an array that changes over time, and we are asked to answer two kinds of queries. One type permanently updates a single position in the array.

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CF 2123D - Binary String Battle

We are given a binary string. Two players alternate moves, with Alice moving first. The game evolves by repeatedly rewriting parts of the string.

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CF 2123E - MEX Count

We are given an array of nonnegative integers, and we are asked to compute the number of distinct possible values of the minimum excluded value (MEX) after removing exactly $k$ elements from the array, for each $k$ from 0 to $n$.

Practice › Codeforces Solutions › Codeforces Round 1034 (Div. 3) ›

CF 2123B - Tournament

We have a tournament with n players. Player i has strength a[i]. Repeatedly, two surviving players are selected, and the weaker one is eliminated. If both strengths are equal, either one may be eliminated. The process stops when exactly k players remain.

Practice › Codeforces Solutions › Codeforces Round 1034 (Div. 3) ›

CF 2123A - Blackboard Game

The blackboard initially contains every integer from 0 to n - 1. A round always has two moves. First Alice removes some number a. Then Bob must remove a different number b such that $$a+b equiv 3 pmod 4.$$ If Bob cannot find such a number, the game ends immediately and Bob loses.

Practice › Codeforces Solutions › Codeforces Round 1034 (Div. 3) ›

CF 2123C - Prefix Min and Suffix Max

We are given an array of distinct integers and a set of operations: you can either replace a prefix with its minimum or a suffix with its maximum.