Codeforces Beta Round 18 (Div. 2 Only)

5 problems from Codeforces Beta Round 18 (Div. 2 Only) (contest 18), difficulty 1200-2000. 5/5 solutions verified against sample I/O.

5 items

Codeforces Beta Round 18 (Div. 2 Only)

Div. 2 | 5 problems | 5/5 verified | Difficulty 1200-2000 | 7m 50s

# Problem Rating Tags Accepted Time ✓
A Triangle 1500 brute-force, geometry 6,946 1m 48s ✓
B Platforms 1700 brute-force, math 2,428 1m 13s ✓
C Stripe 1200 data-structures, implementation 15,416 1m 43s ✓
D Seller Bob 2000 brute-force, dp, greedy 1,290 1m 54s ✓
E Flag 2 2000 dp 1,269 1m 12s ✓
Practice › Codeforces Solutions › Codeforces Beta Round 18 (Div. 2 Only) ›

CF 18A - Triangle

We are given three points on the plane with integer coordinates. These three points already form a valid triangle, meaning they are not collinear.
codeforces competitive-programming brute-force geometry May 28, 2026
Practice › Codeforces Solutions › Codeforces Beta Round 18 (Div. 2 Only) ›

CF 18B - Platforms

We have a line with a series of discrete platforms. Each platform has a fixed length l and is separated from the next by a fixed distance m - l, so platform k occupies the segment from (k-1)m to (k-1)m + l.
codeforces competitive-programming brute-force math May 28, 2026
Practice › Codeforces Solutions › Codeforces Beta Round 18 (Div. 2 Only) ›

CF 18C - Stripe

We have a strip of cells, and each cell contains an integer. We may cut the strip only between adjacent cells, which splits the array into a left part and a right part. The task is to count how many cut positions produce two non-empty parts with equal sums.
codeforces competitive-programming data-structures implementation May 28, 2026
Practice › Codeforces Solutions › Codeforces Beta Round 18 (Div. 2 Only) ›

CF 18D - Seller Bob

Bob experiences one event per day. A day is either a prize day or a customer day.
codeforces competitive-programming brute-force dp greedy May 28, 2026
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CF 18E - Flag 2

We are given a flag represented as an _n_×_m_ grid where each cell is painted with one of 26 colours labeled a to z. The goal is to repaint as few squares as possible so that two conditions hold. First, each row can use at most two different colours.
codeforces competitive-programming dp May 28, 2026