Codeforces Round 721 (Div. 2)

Solutions for Codeforces Round 721 (Div. 2) (contest 1527). 3/6 problems verified against sample I/O. Difficulty range: 800-2500.

6 items

Codeforces Round 721 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 3/6 | Rating range: 800-2500 | Time: 15m 3s

Problem Name Rating Tags Solve Time Verified
A And Then There Were K 800 bitmasks 2m 39s ✗
B1 Palindrome Game (easy version) 1200 constructive-algorithms, games 2m 2s ✓
B2 Palindrome Game (hard version) 1900 constructive-algorithms, games 2m 14s ✓
C Sequence Pair Weight 1600 hashing, implementation, math 1m 34s ✓
D MEX Tree 2400 combinatorics, dfs-and-similar, implementation 3m 53s ✗
E Partition Game 2500 binary-search, data-structures, divide-and-conquer 2m 41s ✗
Practice › Codeforces Solutions › Codeforces Round 721 (Div. 2) ›

CF 1527D - MEX Tree

We have a tree whose vertices are labeled with the integers 0 through n - 1. For every unordered pair of distinct vertices (u, v), we look at the unique simple path connecting them.
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Practice › Codeforces Solutions › Codeforces Round 721 (Div. 2) ›

CF 1527E - Partition Game

Let a multiplication algorithm be called online if it produces the $(k+1)$st output bit of the product $uv$, starting from the least significant bit, only after reading the first $k+1$ input bits of each operand, also from least significant to most significant.
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Practice › Codeforces Solutions › Codeforces Round 721 (Div. 2) ›

CF 1527C - Sequence Pair Weight

We are given several arrays, and for each array we consider every possible contiguous subarray. For each subarray, we define its “weight” as the number of pairs of positions inside it that contain the same value.
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Practice › Codeforces Solutions › Codeforces Round 721 (Div. 2) ›

CF 1527A - And Then There Were K

Let a multiplication algorithm be called online if it produces the $(k+1)$st output bit of the product $uv$, starting from the least significant bit, only after reading the first $k+1$ input bits of each operand, also from least significant to most significant.
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Practice › Codeforces Solutions › Codeforces Round 721 (Div. 2) ›

CF 1527B2 - Palindrome Game (hard version)

We are given a binary string and two players, Alice and Bob, who alternately modify it. A move can either change a single '0' into '1' at a cost of one dollar, or reverse the entire string for free.
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Practice › Codeforces Solutions › Codeforces Round 721 (Div. 2) ›

CF 1527B1 - Palindrome Game (easy version)

We are given a binary string that is already symmetric from both ends. The game starts with Alice and Bob alternating turns, and the only thing that matters financially is how many times each player is forced to flip a character from 0 to 1, since each such flip costs one dollar.
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