Codeforces Round 942 (Div. 2)

Solutions for Codeforces Round 942 (Div. 2) (contest 1972). 1/7 problems verified against sample I/O. Difficulty range: 800-2800.

7 items

Codeforces Round 942 (Div. 2)

Type: Div. 2 | Problems: 7 | Verified: 1/7 | Rating range: 800-2800 | Time: 18m 1s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Contest Proposal	800	brute-force, greedy, two-pointers	2m 28s	✓
B	Coin Games	900	games	3m 56s	✗
C	Permutation Counting	1400	binary-search, constructive-algorithms, greedy	5m 15s	✗
D1	Reverse Card (Easy Version)	1400	brute-force, math, number-theory	1m 56s	✗
D2	Reverse Card (Hard Version)	2200	brute-force, math, number-theory	1m 33s	✗
E	Fenwick Tree	2300	combinatorics, data-structures, math	2m 6s	✗
F	Long Way to be Non-decreasing	2800	binary-search, dfs-and-similar, graphs	47s	✗

Practice › Codeforces Solutions › Codeforces Round 942 (Div. 2) ›

CF 1972E - Fenwick Tree

The problem asks us to reverse-engineer a Fenwick tree, or binary indexed tree, operation. A Fenwick tree s is derived from an array a by summing a specific range for each index k.

Practice › Codeforces Solutions › Codeforces Round 942 (Div. 2) ›

CF 1972C - Permutation Counting

We are given a multiset of cards, each labeled with an integer from 1 to $n$, and for each type $i$ we know how many cards $ai$ we already own. We also have $k$ coins to buy additional cards, and the shop has unlimited supply of each type.

Practice › Codeforces Solutions › Codeforces Round 942 (Div. 2) ›

CF 1972F - Long Way to be Non-decreasing

Connection interrupted. Waiting for the complete answer

Practice › Codeforces Solutions › Codeforces Round 942 (Div. 2) ›

CF 1972B - Coin Games

We are given a circular arrangement of coins. Each coin is either facing up or facing down. Two players alternate turns, and on each turn a player must pick one coin that is currently facing up, remove it, and then flip its two neighbors.

Practice › Codeforces Solutions › Codeforces Round 942 (Div. 2) ›

CF 1972D2 - Reverse Card (Hard Version)

We are asked to count ordered pairs of positive integers (a, b) such that 1 ≤ a ≤ n and 1 ≤ b ≤ m, with an additional divisibility condition: b gcd(a, b) must be divisible by a + b.

Practice › Codeforces Solutions › Codeforces Round 942 (Div. 2) ›

CF 1972D1 - Reverse Card (Easy Version)

We are asked to count how many ordered pairs of integers $(a, b)$ satisfy a divisibility condition under bounded ranges. For each test case, we are given two limits $n$ and $m$.

Practice › Codeforces Solutions › Codeforces Round 942 (Div. 2) ›

CF 1972A - Contest Proposal

We are given a contest with n problems, each having a proposed difficulty ai and an expected maximum difficulty bi. Both sequences are sorted in non-decreasing order. The goal is to adjust the proposed difficulties so that every problem satisfies ai ≤ bi.