Codeforces Round 1093 (Div. 2)

Solutions for Codeforces Round 1093 (Div. 2) (contest 2220). 0/7 problems verified against sample I/O. Difficulty range: 1400-2700.

7 items

Codeforces Round 1093 (Div. 2)

Type: Div. 2 | Problems: 7 | Verified: 0/7 | Rating range: 1400-2700 | Time: 12m 27s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Blocked	-	greedy, sortings	2m 44s	✗
B	OIE Excursion	-	greedy	1m 37s	✗
C	Grid L	1400	brute-force, math	1m 25s	✗
D1	Unique Values (Easy version)	1900	binary-search, interactive	1m 50s	✗
D2	Unique Values (Hard version)	2000	binary-search, interactive	1m 48s	✗
E	Coloring a Red Black Tree	2300	dp, greedy, probabilities	2m 2s	✗
F	MEX Replacement on Tree	2700	-	1m 1s	✗

Practice › Codeforces Solutions › Codeforces Round 1093 (Div. 2) ›

CF 2220E - Coloring a Red Black Tree

We are given a tree with n nodes, where each node is either red or black. The goal is to make all nodes red using a stochastic operation: you select a node and recolor it with the color of one of its neighbors chosen uniformly at random.

Practice › Codeforces Solutions › Codeforces Round 1093 (Div. 2) ›

CF 2220D2 - Unique Values (Hard version)

We are given an array of length $2n+1$. Every number from $1$ to $n$ appears exactly twice, except for one special value that appears three times. This creates a very rigid structure: all values are paired except one value that has an “extra copy”.

Practice › Codeforces Solutions › Codeforces Round 1093 (Div. 2) ›

CF 2220F - MEX Replacement on Tree

We have a rooted tree. Every vertex carries a unique value from the permutation $0,1,dots,n-1$. For a vertex $v$, look at all vertices on the root-to-$v$ path. Their values form a set $Sv$.

Practice › Codeforces Solutions › Codeforces Round 1093 (Div. 2) ›

CF 2220D1 - Unique Values (Easy version)

In the original interactive problem, there is a hidden array of length $2n+1$. Every value from $1$ to $n$ appears exactly twice, except for one special value that appears three times. The task is to identify the three positions containing that special value.

Practice › Codeforces Solutions › Codeforces Round 1093 (Div. 2) ›

CF 2220A - Blocked

We are given two nonnegative integers (x) and (y). We must construct two new nonnegative integers (p) and (q) such that no bit is set in both numbers simultaneously, that is, [ p ,&, q = 0.

Practice › Codeforces Solutions › Codeforces Round 1093 (Div. 2) ›

CF 2220C - Grid L

We are given two types of building blocks: unit-length segments and L-shaped pieces made of two segments joined at a right angle. We need to construct a rectangular grid with dimensions $n times m$ so that every piece is used exactly once.

Practice › Codeforces Solutions › Codeforces Round 1093 (Div. 2) ›

CF 2220B - OIE Excursion

We are given a line of positions from 1 to n, each guarded by a volunteer. Hector starts at position 0 and wants to reach position n+1 by moving one step left, right, or staying still at the end of each second. Each volunteer has a timer that evolves deterministically.