Codeforces Round 872 (Div. 2)

Solutions for Codeforces Round 872 (Div. 2) (contest 1825). 4/6 problems verified against sample I/O. Difficulty range: 800-2500.

6 items

Codeforces Round 872 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 4/6 | Rating range: 800-2500 | Time: 8m 24s

Problem	Name	Rating	Tags	Solve Time	Verified
A	LuoTianyi and the Palindrome String	800	greedy, strings	1m 13s	✓
B	LuoTianyi and the Table	1000	greedy, math	1m 28s	✗
C	LuoTianyi and the Show	1400	greedy, sortings	1m 51s	✗
D1	LuoTianyi and the Floating Islands (Easy Version)	1800	combinatorics, dp, math	1m 34s	✓
D2	LuoTianyi and the Floating Islands (Hard Version)	2300	combinatorics, dfs-and-similar, math	1m 2s	✓
E	LuoTianyi and XOR-Tree	2500	data-structures, dp, dsu	1m 16s	✓

Practice › Codeforces Solutions › Codeforces Round 872 (Div. 2) ›

CF 1825E - LuoTianyi and XOR-Tree

We are given a rooted tree with n vertices, each labeled with a non-negative integer. The root is vertex 1. We are allowed to change the value of any vertex to any non-negative integer, and our goal is to minimize the number of changes required so that the bitwise XOR of the…

Practice › Codeforces Solutions › Codeforces Round 872 (Div. 2) ›

CF 1825D1 - LuoTianyi and the Floating Islands (Easy Version)

We are given a tree with $n$ nodes, representing islands connected by $n-1$ bidirectional routes. From this tree, we randomly choose $k$ distinct nodes, where $k le 3$. These chosen nodes represent the locations of people.

Practice › Codeforces Solutions › Codeforces Round 872 (Div. 2) ›

CF 1825D2 - LuoTianyi and the Floating Islands (Hard Version)

We have a set of $n$ islands connected in a tree structure. That means any two islands are connected by exactly one path, and there are $n-1$ edges. LuoTianyi wants to meet $k$ friends, each located on a distinct island.

Practice › Codeforces Solutions › Codeforces Round 872 (Div. 2) ›

CF 1825C - LuoTianyi and the Show

We are given a row of seats numbered from 1 to $m$ and $n$ people arriving in a show. Each person has a preferred seating type: they either want to sit immediately to the left of the leftmost occupied seat, immediately to the right of the rightmost occupied seat, or in a…

Practice › Codeforces Solutions › Codeforces Round 872 (Div. 2) ›

CF 1825B - LuoTianyi and the Table

We are given a flat list of n m integers and asked to fill them into an n-by-m table. After filling, we compute a sum over all submatrices that start at the top-left corner (1,1) and end at each position (i,j).

Practice › Codeforces Solutions › Codeforces Round 872 (Div. 2) ›

CF 1825A - LuoTianyi and the Palindrome String

We are given a string that is guaranteed to be a palindrome. The task is to find the longest subsequence of this string that is not a palindrome.