Codeforces Round 900 (Div. 3)

Solutions for Codeforces Round 900 (Div. 3) (contest 1878). 4/7 problems verified against sample I/O. Difficulty range: 800-2300.

7 items

Codeforces Round 900 (Div. 3)

Type: Div. 3 | Problems: 7 | Verified: 4/7 | Rating range: 800-2300 | Time: 12m 56s

Problem	Name	Rating	Tags	Solve Time	Verified
A	How Much Does Daytona Cost?	800	greedy	1m 46s	✓
B	Aleksa and Stack	800	constructive-algorithms, math	2m 16s	✗
C	Vasilije in Cacak	900	math	1m 27s	✓
D	Reverse Madness	1600	data-structures, greedy	1m 31s	✓
E	Iva & Pav	1400	binary-search, bitmasks, data-structures	2m 21s	✗
F	Vasilije Loves Number Theory	1900	brute-force, math, number-theory	1m 52s	✗
G	wxhtzdy ORO Tree	2300	binary-search, bitmasks, brute-force	1m 43s	✓

Practice › Codeforces Solutions › Codeforces Round 900 (Div. 3) ›

CF 1878G - wxhtzdy ORO Tree

We are given a tree where each vertex carries a small integer value. For any two vertices $u$ and $v$, we define a function that aggregates all values along the unique simple path between them using bitwise OR. This produces a single number summarizing the entire path.

Practice › Codeforces Solutions › Codeforces Round 900 (Div. 3) ›

CF 1878F - Vasilije Loves Number Theory

We are maintaining a single integer that changes over time, and after each update we need to answer whether it is possible to “complete” it into a very specific divisor structure using an auxiliary number that shares no prime factors with the current value.

Practice › Codeforces Solutions › Codeforces Round 900 (Div. 3) ›

CF 1878E - Iva & Pav

We are given an array of integers and multiple queries. Each query specifies a starting index $l$ and a threshold $k$. The task is to find the largest ending index $r ge l$ such that the bitwise AND of the subarray from $al$ to $ar$ is at least $k$.

Practice › Codeforces Solutions › Codeforces Round 900 (Div. 3) ›

CF 1878D - Reverse Madness

We are given a string indexed from 1 to n, and the index range is partitioned into k consecutive segments. Each segment i covers a continuous interval from li to ri, and these segments exactly tile the entire string without gaps or overlaps. We then process a sequence of queries.

Practice › Codeforces Solutions › Codeforces Round 900 (Div. 3) ›

CF 1878B - Aleksa and Stack

We are asked to build a strictly increasing array of length $n$, where each element is a positive integer, and $n ge 3$.

Practice › Codeforces Solutions › Codeforces Round 900 (Div. 3) ›

CF 1878A - How Much Does Daytona Cost?

The problem asks whether, given an array of integers and a target integer $k$, there exists at least one contiguous subarray in which $k$ is the element that appears more frequently than any other element.

Practice › Codeforces Solutions › Codeforces Round 900 (Div. 3) ›

CF 1878C - Vasilije in Cacak

The problem asks whether we can pick exactly k distinct integers from the set {1, 2, ..., n} such that their sum equals x. Each test case provides three integers: n, the upper bound of the numbers we can choose; k, the number of elements we must select; and x, the target sum.