Codeforces Round 991 (Div. 3)

7 problems from Codeforces Round 991 (Div. 3) (contest 2050), difficulty 800-1900. 4/7 solutions verified against sample I/O.

7 items

Codeforces Round 991 (Div. 3)

Div. 3 | 7 problems | 4/7 verified | Difficulty 800-1900 | 14m 3s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Line Breaks	800	implementation	36,453	1m 35s	✓
B	Transfusion	1100	brute-force, greedy, math	27,049	2m 13s
C	Uninteresting Number	1200	brute-force, dp, math	24,991	1m 15s	✓
D	Digital string maximization	1300	brute-force, greedy, math	18,971	3m 30s
E	Three Strings	1500	dp, implementation, strings	14,493	1m 27s	✓
F	Maximum modulo equality	1700	data-structures, divide-and-conquer, math	10,595	2m 50s
G	Tree Destruction	1900	dfs-and-similar, dp, trees	5,378	1m 13s	✓

Practice › Codeforces Solutions › Codeforces Round 991 (Div. 3) ›

CF 2050F - Maximum modulo equality

Thank you for the clarification. I see exactly why the previous solution fails. The core issue is that the greedy left-to-right redistribution is too strict: it assumes you can only push surplus to the next element, but in reality the allowed operations let you shift values…

Practice › Codeforces Solutions › Codeforces Round 991 (Div. 3) ›

CF 2050D - Digital string maximization

We are given a string of digits, representing a number without leading zeros. We can repeatedly perform a restricted operation: pick any digit except the leftmost one or zero, decrease it by one, and swap it with the digit immediately to its left.

Practice › Codeforces Solutions › Codeforces Round 991 (Div. 3) ›

CF 2050G - Tree Destruction

We are given a tree, which is an acyclic connected graph, with $n$ vertices. The task is to select two vertices, $a$ and $b$, and remove all vertices along the unique path between them, including $a$ and $b$ themselves.

Practice › Codeforces Solutions › Codeforces Round 991 (Div. 3) ›

CF 2050E - Three Strings

We are given three strings: a, b, and c. Conceptually, c is formed by taking letters from a and b in some interleaving order. At each step, one letter is taken from the front of either a or b and appended to c.

Practice › Codeforces Solutions › Codeforces Round 991 (Div. 3) ›

CF 2050B - Transfusion

We are given an array of integers representing “pools” of some resource. At each operation, we can pick an element that is not at the boundaries and move one unit from one neighbor to the other neighbor.

Practice › Codeforces Solutions › Codeforces Round 991 (Div. 3) ›

CF 2050A - Line Breaks

We are given a list of words and a fixed-length strip that can hold a certain number of characters. The task is to decide how many words we can consecutively place on this first strip without exceeding its length, while the remaining words go on a second strip that has…

Practice › Codeforces Solutions › Codeforces Round 991 (Div. 3) ›

CF 2050C - Uninteresting Number

We are given a very long decimal string, and we are allowed to repeatedly modify it digit by digit. A move picks one digit, replaces it with the value of its square, and keeps it as a single decimal digit only if the square is still between 0 and 9.