Educational Codeforces Round 153 (Rated for Div. 2)

Solutions for Educational Codeforces Round 153 (Rated for Div. 2) (contest 1860). 3/6 problems verified against sample I/O. Difficulty range: 900-2900.

6 items

Educational Codeforces Round 153 (Rated for Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 3/6 | Rating range: 900-2900 | Time: 11m 13s

Problem Name Rating Tags Solve Time Verified
A Not a Substring 900 constructive-algorithms, strings 2m 4s ✗
B Fancy Coins 1200 binary-search, brute-force, greedy 1m 46s ✓
C Game on Permutation 1400 data-structures, dp, games 1m 56s ✗
D Balanced String 2200 dp 1m 19s ✓
E Fast Travel Text Editor 2400 data-structures, dfs-and-similar, graphs 2m 40s ✗
F Evaluate RBS 2900 data-structures, geometry, implementation 1m 28s ✓
Practice › Codeforces Solutions › Educational Codeforces Round 153 (Rated for Div. 2) ›

CF 1860E - Fast Travel Text Editor

We are given a string and a cursor that initially sits between two letters. The cursor can move left or right by one position, and it can also "teleport" between any two adjacent letters x and y if there exists another pair x followed by y elsewhere in the string.
codeforces competitive-programming data-structures dfs-and-similar graphs shortest-paths Jun 9, 2026
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CF 1860F - Evaluate RBS

We are given $2n$ tuples of the form $(a, b, c)$, where $a$ and $b$ are positive integers and $c$ is a bracket, either '(' or ')'. Exactly half of the tuples are opening brackets and the other half are closing brackets.
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CF 1860D - Balanced String

We are given a binary string, and we are allowed to reorder it using swaps between any two positions. The cost of each operation is one swap, and swaps are unrestricted in the sense that we can choose any pair of indices.
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CF 1860A - Not a Substring

We are given a string s consisting only of parentheses, and we need to construct a new string t of length exactly twice that of s, such that t forms a valid bracket sequence and s does not appear anywhere inside t as a contiguous substring.
codeforces competitive-programming constructive-algorithms strings Jun 9, 2026
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CF 1860C - Game on Permutation

We are given a permutation and a game played on its positions. The chip starts nowhere. Alice begins by choosing any position and placing the chip there. After that, players alternate moving the chip.
codeforces competitive-programming data-structures dp games greedy Jun 9, 2026
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CF 1860B - Fancy Coins

We are asked to determine the minimum number of fancy coins Monocarp must use to pay exactly m burles when he has two types of coins: one worth 1 burle and one worth k burles.
codeforces competitive-programming binary-search brute-force greedy math Jun 9, 2026