Educational Codeforces Round 64 (Rated for Div. 2)

Solutions for Educational Codeforces Round 64 (Rated for Div. 2) (contest 1156). 4/7 problems verified against sample I/O. Difficulty range: 1400-2700.

7 items

Educational Codeforces Round 64 (Rated for Div. 2)

Type: Div. 2 | Problems: 7 | Verified: 4/7 | Rating range: 1400-2700 | Time: 10m 55s

Problem Name Rating Tags Solve Time Verified
A Inscribed Figures 1400 geometry 1m 31s ✓
B Ugly Pairs 1800 dfs-and-similar, greedy, implementation 1m 46s ✗
C Match Points 2000 binary-search, greedy, sortings 1m 18s ✓
D 0-1-Tree 2200 dfs-and-similar, divide-and-conquer, dp 1m 42s ✗
E Special Segments of Permutation 2200 data-structures, divide-and-conquer, dsu 1m 41s ✓
F Card Bag 2300 dp, math, probabilities 1m 28s ✓
G Optimizer 2700 graphs, greedy, hashing 1m 29s ✗
Practice › Codeforces Solutions › Educational Codeforces Round 64 (Rated for Div. 2) ›

CF 1156G - Optimizer

We are given a program written in a strange language where each variable has a short name of up to four alphanumeric characters, with the first character not being a digit.
codeforces competitive-programming graphs greedy hashing implementation Jun 12, 2026
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CF 1156F - Card Bag

We are repeatedly drawing cards from a multiset of values, without replacement. The only thing that matters is the sequence of drawn values, and how each value compares to the previous drawn value. The game behaves like this: the first drawn card just sets a baseline value.
codeforces competitive-programming dp math probabilities Jun 12, 2026
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CF 1156E - Special Segments of Permutation

We are given a permutation of the numbers from 1 to n. For every subarray [l, r], we look at its maximum value. The subarray is called special when the sum of the two endpoint values equals that maximum: $$pl + pr = max(pl,dots,pr)$$ The task is to count how many subarrays…
codeforces competitive-programming data-structures divide-and-conquer dsu two-pointers Jun 12, 2026
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CF 1156D - 0-1-Tree

We are given a tree with n vertices, where each edge is labeled either 0 or 1. We need to count all ordered pairs of distinct vertices (x, y) such that, when walking along the unique path from x to y, we never traverse a 0-edge after we have already traversed a 1-edge.
codeforces competitive-programming dfs-and-similar divide-and-conquer dp dsu trees Jun 12, 2026
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CF 1156B - Ugly Pairs

We are given a short string of lowercase letters and we are allowed to reorder its characters arbitrarily. The goal is to produce an arrangement where no two adjacent characters differ by exactly one position in the alphabet.
codeforces competitive-programming dfs-and-similar greedy implementation sortings strings Jun 12, 2026
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CF 1156A - Inscribed Figures

We are given a sequence of geometric figures. Each number represents one of three shapes: - 1 = circle - 2 = isosceles triangle whose height equals its base length - 3 = square Every figure is inscribed into the previous one and is chosen with the largest possible size.
codeforces competitive-programming geometry Jun 12, 2026
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CF 1156C - Match Points

We are given a collection of points placed on a number line, and the goal is to form as many disjoint pairs as possible.
codeforces competitive-programming binary-search greedy sortings ternary-search two-pointers Jun 12, 2026