Codeforces Round 813 (Div. 2)

7 problems from Codeforces Round 813 (Div. 2) (contest 1712), difficulty 800-3200. 2/7 solutions verified against sample I/O.

7 items

Codeforces Round 813 (Div. 2)

Div. 2 | 7 problems | 2/7 verified | Difficulty 800-3200 | 23m 35s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Wonderful Permutation	800	greedy, implementation	25,056	1m 53s	✓
B	Woeful Permutation	800	constructive-algorithms, greedy, number-theory	22,398	3m 43s	✓
C	Sort Zero	1100	greedy, sortings	21,266	3m 47s
D	Empty Graph	2000	binary-search, constructive-algorithms, data-structures	5,102	3m 52s
E1	LCM Sum (easy version)	2300	binary-search, brute-force, combinatorics	2,460	3m 36s
E2	LCM Sum (hard version)	2500	brute-force, data-structures, math	1,613	3m 37s
F	Triameter	3200	binary-search, data-structures, dfs-and-similar	443	3m 7s

Practice › Codeforces Solutions › Codeforces Round 813 (Div. 2) ›

CF 1712E2 - LCM Sum (hard version)

We are given many queries, and each query describes a contiguous interval of integers from l to r. For each such interval, we want to count how many triples (i, j, k) can be formed with strictly increasing indices inside the interval such that the least common multiple of the…

Practice › Codeforces Solutions › Codeforces Round 813 (Div. 2) ›

CF 1712E1 - LCM Sum (easy version)

We are given many independent queries, each query defines a numeric segment from $l$ to $r$. Inside that segment we consider all triples of distinct indices $i < j < k$, and we want to count how many of these triples satisfy a specific inequality: the least common multiple of…

Practice › Codeforces Solutions › Codeforces Round 813 (Div. 2) ›

CF 1712F - Triameter

We are given a tree with unit-weight edges. From this tree we identify a special set of vertices, the leaves, meaning the vertices whose degree is exactly one.

Practice › Codeforces Solutions › Codeforces Round 813 (Div. 2) ›

CF 1712D - Empty Graph

We are given an array where each position represents a node in a line. Between any two indices $l$ and $r$, there is an edge whose weight is the minimum value in the subarray $al, dots, ar$.

Practice › Codeforces Solutions › Codeforces Round 813 (Div. 2) ›

CF 1712C - Sort Zero

We are given several independent test cases, each consisting of an array of positive integers. In one move, we are allowed to pick a value x and simultaneously erase all occurrences of x in the array by turning them into zeros.

Practice › Codeforces Solutions › Codeforces Round 813 (Div. 2) ›

CF 1712B - Woeful Permutation

We are given a single integer $n$, and we must arrange the numbers from $1$ to $n$ into a permutation so that a particular score is as large as possible.

Practice › Codeforces Solutions › Codeforces Round 813 (Div. 2) ›

CF 1712A - Wonderful Permutation

We are given a permutation of integers from 1 to $n$, meaning every number from 1 through $n$ appears exactly once, in some arbitrary order. The task is to minimize the sum of the first $k$ elements in this permutation by performing swaps between any two positions.