Codeforces Round 278 (Div. 1)

5 problems from Codeforces Round 278 (Div. 1) (contest 487), difficulty 1800-3200. 3/5 solutions verified against sample I/O.

5 items

Codeforces Round 278 (Div. 1)

Div. 1 | 5 problems | 3/5 verified | Difficulty 1800-3200 | 10m 16s

# Problem Rating Tags Accepted Time ✓
A Fight the Monster 1800 binary-search, brute-force, implementation 3,952 2m 6s ✓
B Strip 2000 binary-search, data-structures, dp 4,209 1m 42s ✓
C Prefix Product Sequence 2300 constructive-algorithms, math, number-theory 3,079 2m 42s
D Conveyor Belts 2700 data-structures 1,005 2m 3s ✓
E Tourists 3200 data-structures, dfs-and-similar, graphs 2,839 1m 43s
Practice › Codeforces Solutions › Codeforces Round 278 (Div. 1) ›

CF 487E - Tourists

We are asked to handle queries on a connected undirected graph representing cities in Cyberland. Each city has a souvenir price, and roads connect pairs of cities.
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Practice › Codeforces Solutions › Codeforces Round 278 (Div. 1) ›

CF 487D - Conveyor Belts

We are given a rectangular table of size n by m filled with conveyor belts. Each conveyor belt points either up (^), left (<), or right (). Surrounding the table are diner seats, numbered logically as rows 0 and n+1 and columns 0 and m+1.
codeforces competitive-programming data-structures Jun 7, 2026
Practice › Codeforces Solutions › Codeforces Round 278 (Div. 1) ›

CF 487C - Prefix Product Sequence

We need to arrange the numbers $1,2,dots,n$ into a permutation $a1,a2,dots,an$. Define $$pi = a1a2cdots ai pmod n.$$ The requirement is that the sequence $p1,p2,dots,pn$ must itself be a permutation of all residues $0,1,dots,n-1$.
codeforces competitive-programming constructive-algorithms math number-theory Jun 7, 2026
Practice › Codeforces Solutions › Codeforces Round 278 (Div. 1) ›

CF 487A - Fight the Monster

We are given the initial combat statistics of two characters, Master Yang and a monster. Each character has hit points, attack, and defense. Combat proceeds in discrete seconds.
codeforces competitive-programming binary-search brute-force implementation Jun 7, 2026
Practice › Codeforces Solutions › Codeforces Round 278 (Div. 1) ›

CF 487B - Strip

We have an array of integers representing numbers on a strip of paper. Alexandra wants to divide the strip into contiguous segments. Each segment must have at least l numbers, and the difference between the largest and smallest number in that segment must not exceed s.
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