Codeforces Round 551 (Div. 2)

Solutions for Codeforces Round 551 (Div. 2) (contest 1153). 3/6 problems verified against sample I/O. Difficulty range: 1000-2600.

6 items

Codeforces Round 551 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 3/6 | Rating range: 1000-2600 | Time: 12m 1s

Problem Name Rating Tags Solve Time Verified
A Serval and Bus 1000 brute-force, math 1m 43s ✓
B Serval and Toy Bricks 1200 constructive-algorithms, greedy 2m 25s ✗
C Serval and Parenthesis Sequence 1700 greedy, strings 1m 58s ✗
D Serval and Rooted Tree 1900 binary-search, dfs-and-similar, dp 1m 23s ✓
E Serval and Snake 2200 binary-search, brute-force, interactive 2m 16s ✗
F Serval and Bonus Problem 2600 combinatorics, dp, math 2m 16s ✓
Practice › Codeforces Solutions › Codeforces Round 551 (Div. 2) ›

CF 1153F - Serval and Bonus Problem

We are asked to consider a line segment of length $l$. We randomly choose $n$ subsegments on this line. Each subsegment is determined by picking two points uniformly at random on the segment, so their endpoints may be non-integer.
codeforces competitive-programming combinatorics dp math probabilities Jun 12, 2026
Practice › Codeforces Solutions › Codeforces Round 551 (Div. 2) ›

CF 1153E - Serval and Snake

We are given a hidden simple path drawn on an $n times n$ grid. The path represents a snake: it visits distinct cells, each consecutive pair shares a side, and the two ends of the path are special cells called the head and the tail. We cannot see the path directly.
codeforces competitive-programming binary-search brute-force interactive Jun 12, 2026
Practice › Codeforces Solutions › Codeforces Round 551 (Div. 2) ›

CF 1153D - Serval and Rooted Tree

We are given a rooted tree where every node either behaves like a minimum aggregator or a maximum aggregator. The leaves do not compute anything; they simply hold values.
codeforces competitive-programming binary-search dfs-and-similar dp greedy trees Jun 12, 2026
Practice › Codeforces Solutions › Codeforces Round 551 (Div. 2) ›

CF 1153B - Serval and Toy Bricks

We are given a 3-dimensional arrangement of unit bricks arranged in an $n times m$ grid. The height of bricks at position $(i,j)$ is unknown, but we are provided with three partial views: the front, the left, and the top.
codeforces competitive-programming constructive-algorithms greedy Jun 12, 2026
Practice › Codeforces Solutions › Codeforces Round 551 (Div. 2) ›

CF 1153C - Serval and Parenthesis Sequence

We are given a string consisting of three types of characters: open parenthesis "(", close parenthesis ")", and question marks "?". Our goal is to replace each "?
codeforces competitive-programming greedy strings Jun 12, 2026
Practice › Codeforces Solutions › Codeforces Round 551 (Div. 2) ›

CF 1153A - Serval and Bus

Serval is going to the bus station at a specific time t. There are n bus routes, each with a first bus arriving at si minutes and subsequent buses every di minutes. Serval will take the first bus that comes after or exactly at time t.
codeforces competitive-programming brute-force math Jun 12, 2026