Educational Codeforces Round 129 (Rated for Div. 2)

Solutions for Educational Codeforces Round 129 (Rated for Div. 2) (contest 1681). 3/6 problems verified against sample I/O. Difficulty range: 800-2600.

6 items

Educational Codeforces Round 129 (Rated for Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 3/6 | Rating range: 800-2600 | Time: 19m 35s

Problem Name Rating Tags Solve Time Verified
A Game with Cards 800 games, greedy 10m 58s ✗
B Card Trick 800 implementation, math 1m 37s ✓
C Double Sort 1200 implementation, sortings 2m 5s ✗
D Required Length 1700 brute-force, dfs-and-similar, dp 1m 25s ✓
E Labyrinth Adventures 2600 data-structures, dp, matrices 2m 1s ✗
F Unique Occurrences 2300 data-structures, dfs-and-similar, divide-and-conquer 1m 29s ✓
Practice › Codeforces Solutions › Educational Codeforces Round 129 (Rated for Div. 2) ›

CF 1681A - Game with Cards

Two players each hold a multiset of integers. They play a turn-based game where the only rule is that every newly played number must be strictly larger than the previous one.
codeforces competitive-programming games greedy Jun 10, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 129 (Rated for Div. 2) ›

CF 1681F - Unique Occurrences

We are given a tree with $n$ vertices. Each edge has an integer label. For any pair of vertices $v$ and $u$, we define $f(v, u)$ as the number of edge labels that appear exactly once along the unique path connecting $v$ and $u$.
codeforces competitive-programming data-structures dfs-and-similar divide-and-conquer dp dsu trees Jun 10, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 129 (Rated for Div. 2) ›

CF 1681E - Labyrinth Adventures

We are given a labyrinth structured as concentric layers in an $n times n$ grid. Each layer is a contiguous set of cells surrounding the previous layer. The first layer is just the bottom-left corner.
codeforces competitive-programming data-structures dp matrices shortest-paths Jun 10, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 129 (Rated for Div. 2) ›

CF 1681D - Required Length

We are given an integer x and a target length n. We can repeatedly choose any digit y from the current number x and multiply x by y. The goal is to make x have exactly n digits using the minimum number of such operations.
codeforces competitive-programming brute-force dfs-and-similar dp hashing shortest-paths Jun 10, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 129 (Rated for Div. 2) ›

CF 1681C - Double Sort

We are given two arrays of the same length, a and b. We can perform a special swap operation: choose any two positions i and j, and simultaneously swap a[i] with a[j] and b[i] with b[j].
codeforces competitive-programming implementation sortings Jun 10, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 129 (Rated for Div. 2) ›

CF 1681B - Card Trick

We are given a deck of n cards with distinct integer values, ordered from top to bottom. We then perform m shuffle operations, each defined by a number bj.
codeforces competitive-programming implementation math Jun 10, 2026