Educational Codeforces Round 107 (Rated for Div. 2)

7 problems from Educational Codeforces Round 107 (Rated for Div. 2) (contest 1511), difficulty 800-2700. 4/7 solutions verified against sample I/O.

7 items

Educational Codeforces Round 107 (Rated for Div. 2)

Div. 2 | 7 problems | 4/7 verified | Difficulty 800-2700 | 28m 26s

# Problem Rating Tags Accepted Time ✓
A Review Site 800 greedy 28,825 3m 35s ✓
B GCD Length 1100 constructive-algorithms, math, number-theory 24,678 7m 5s
C Yet Another Card Deck 1100 brute-force, data-structures, implementation 32,792 2m 13s ✓
D Min Cost String 1600 brute-force, constructive-algorithms, graphs 12,449 3m 58s
E Colorings and Dominoes 2100 combinatorics, dp, greedy 2,895 3m 4s ✓
F Chainword 2700 brute-force, data-structures, dp 542 5m 50s
G Chips on a Board 2700 bitmasks, brute-force, data-structures 939 2m 41s ✓
Practice › Codeforces Solutions › Educational Codeforces Round 107 (Rated for Div. 2) ›

CF 1511F - Chainword

We are building strings of length $m$, but the string itself is not the only object we care about. Along with the string, we also choose two independent ways to split it into consecutive segments. Each segment must correspond exactly to one of the dictionary words.
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Practice › Codeforces Solutions › Educational Codeforces Round 107 (Rated for Div. 2) ›

CF 1511B - GCD Length

We are asked to construct two positive integers, call them $x$ and $y$, such that we fully control three properties at once: how many digits $x$ has, how many digits $y$ has, and how many digits their greatest common divisor has.
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Practice › Codeforces Solutions › Educational Codeforces Round 107 (Rated for Div. 2) ›

CF 1511D - Min Cost String

We are asked to construct a string of length n using only the first k lowercase Latin letters. Among all possible such strings, we want one that minimizes a specific cost function. The cost is defined over adjacent pairs inside the string.
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Practice › Codeforces Solutions › Educational Codeforces Round 107 (Rated for Div. 2) ›

CF 1511A - Review Site

Each test gives a sequence of reviewers arriving one after another. Every reviewer must be sent to one of two identical servers. Each server maintains its own counters of upvotes and downvotes, and these counters influence future decisions only on that same server.
codeforces competitive-programming greedy Jun 14, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 107 (Rated for Div. 2) ›

CF 1511G - Chips on a Board

We are given a rectangular board with n rows and m columns. Each row contains exactly one chip. The chips can be located in any column of their respective row.
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Practice › Codeforces Solutions › Educational Codeforces Round 107 (Rated for Div. 2) ›

CF 1511E - Colorings and Dominoes

We are given a grid where some cells are blocked and the remaining cells are usable. Every usable cell must be colored either red or blue. After choosing a coloring, we want to place as many dominoes as possible.
codeforces competitive-programming combinatorics dp greedy math Jun 10, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 107 (Rated for Div. 2) ›

CF 1511C - Yet Another Card Deck

We are given a deck of n cards, each with a color represented by an integer from 1 to 50. The deck is arranged from top to bottom, and we receive q queries.
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