Codeforces Global Round 7

6 problems from Codeforces Global Round 7 (contest 1326), difficulty 1000-3500. 2/6 solutions verified against sample I/O.

6 items

Codeforces Global Round 7

Global | 6 problems | 2/6 verified | Difficulty 1000-3500 | 24m 1s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Bad Ugly Numbers	1000	constructive-algorithms, number-theory	32,675	2m 55s
D1	Prefix-Suffix Palindrome (Easy version)	1500	hashing, string-suffix-structures, strings	13,292	1m 10s	✓
D2	Prefix-Suffix Palindrome (Hard version)	1800	binary-search, greedy, hashing	11,749	5m 40s
E	Bombs	2400	data-structures, two-pointers	2,420	8m 17s
F2	Wise Men (Hard Version)	3200	bitmasks, dp, math	679	2m 36s	✓
G	Spiderweb Trees	3500	dp, geometry, trees	108	3m 23s

Practice › Codeforces Solutions › Codeforces Global Round 7 ›

CF 1326E - Bombs

We are given a permutation p, which we can think of as values arriving in a fixed order from position 1 to n. While processing this order, we maintain a multiset A. Each time we process position i, we insert p[i] into A.

Practice › Codeforces Solutions › Codeforces Global Round 7 ›

CF 1326D2 - Prefix-Suffix Palindrome (Hard version)

We are given a string and we want to build the longest possible palindrome that can be formed by taking a prefix of the string, a suffix of the string, or both, and concatenating them in that order.

Practice › Codeforces Solutions › Codeforces Global Round 7 ›

CF 1326G - Spiderweb Trees

We are given a geometric tree: each vertex is a point in the plane and edges form a non-crossing tree. This already means the embedding is fixed, so geometric notions like convex hull are meaningful relative to the given drawing.

Practice › Codeforces Solutions › Codeforces Global Round 7 ›

CF 1326F2 - Wise Men (Hard Version)

We are asked to analyze permutations of a group of $n$ wise men, where some pairs of them know each other. For each permutation of these wise men, we can create a binary string of length $n-1$ indicating adjacency of acquaintances: a '1' if two consecutive wise men in the…

Practice › Codeforces Solutions › Codeforces Global Round 7 ›

CF 1326A - Bad Ugly Numbers

We need to construct a positive decimal number with exactly n digits. Every digit must be nonzero, and the whole number must fail divisibility by each digit that appears in it. For each test case, the input gives only the required length n.

Practice › Codeforces Solutions › Codeforces Global Round 7 ›

CF 1326D1 - Prefix-Suffix Palindrome (Easy version)

We are given a string consisting of lowercase English letters, and the task is to construct the longest palindrome by combining a prefix and a suffix of this string.