Codeforces Round 277 (Div. 2)

5 problems from Codeforces Round 277 (Div. 2) (contest 486), difficulty 800-2200. 5/5 solutions verified against sample I/O.

5 items

Codeforces Round 277 (Div. 2)

Div. 2 | 5 problems | 5/5 verified | Difficulty 800-2200 | 9m 11s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Calculating Function	800	implementation, math	154,077	1m 34s	✓
B	OR in Matrix	1300	greedy, hashing, implementation	19,167	1m 32s	✓
C	Palindrome Transformation	1700	brute-force, greedy, implementation	12,370	1m 44s	✓
D	Valid Sets	2100	dfs-and-similar, dp, math	4,380	1m 58s	✓
E	LIS of Sequence	2200	data-structures, dp, greedy	2,627	2m 23s	✓

Practice › Codeforces Solutions › Codeforces Round 277 (Div. 2) ›

CF 486E - LIS of Sequence

We are given an array and we care about its longest increasing subsequences. An index belongs to a longest increasing subsequence if the value at that position is selected as one of the elements of that subsequence. The task is not to count LISs.

Practice › Codeforces Solutions › Codeforces Round 277 (Div. 2) ›

CF 486D - Valid Sets

We are given a tree where every vertex has an integer value. A set of vertices is considered valid if it is non-empty, forms a connected subgraph of the tree, and the difference between the largest and smallest value inside the set does not exceed d.

Practice › Codeforces Solutions › Codeforces Round 277 (Div. 2) ›

CF 486C - Palindrome Transformation

We are given a string of length $n$ consisting of lowercase English letters, along with a cursor position $p$ that can move left or right around the string in a cyclic manner.

Practice › Codeforces Solutions › Codeforces Round 277 (Div. 2) ›

CF 486A - Calculating Function

We are given a single integer n and asked to evaluate the alternating sum $$-1 + 2 - 3 + 4 - 5 + dots + (-1)^n n.$$ The sign of each term depends on its position. Odd numbers are subtracted and even numbers are added. The output is the final value of this sum.

Practice › Codeforces Solutions › Codeforces Round 277 (Div. 2) ›

CF 486B - OR in Matrix

We are given a matrix B of size m × n, where each element is either 0 or 1. This matrix was supposedly generated from some original matrix A of the same size using a specific rule: each element B[i][j] equals the logical OR of all elements in the i-th row of A combined with…