Codeforces Round 849 (Div. 4)

Solutions for Codeforces Round 849 (Div. 4) (contest 1791). 7/8 problems verified against sample I/O. Difficulty range: 800-1900.

8 items

Codeforces Round 849 (Div. 4)

Type: Div. 4 | Problems: 8 | Verified: 7/8 | Rating range: 800-1900 | Time: 17m 17s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Codeforces Checking	800	implementation, strings	1m 3s	✓
B	Following Directions	800	geometry, implementation	2m 33s	✓
C	Prepend and Append	800	implementation, two-pointers	1m 15s	✓
D	Distinct Split	1000	brute-force, greedy, strings	3m 41s	✓
E	Negatives and Positives	1100	dp, greedy, sortings	2m 13s	✓
F	Range Update Point Query	1500	binary-search, brute-force, data-structures	3m 14s	✓
G1	Teleporters (Easy Version)	1100	greedy, sortings	1m 5s	✓
G2	Teleporters (Hard Version)	1900	binary-search, greedy, sortings	2m 13s	✗

Practice › Codeforces Solutions › Codeforces Round 849 (Div. 4) ›

CF 1791G2 - Teleporters (Hard Version)

We are given a number line with positions labeled from 0 to n+1. Positions 1 through n each have a teleporter with a specified cost.

Practice › Codeforces Solutions › Codeforces Round 849 (Div. 4) ›

CF 1791F - Range Update Point Query

We are given an array of integers and a series of operations that either transform a subarray by replacing each element with the sum of its digits or query the current value of a single element. The task is to output the results of all the queries in the order they appear.

Practice › Codeforces Solutions › Codeforces Round 849 (Div. 4) ›

CF 1791D - Distinct Split

We are asked to split a string into two non-empty parts such that the sum of distinct characters in each part is maximized.

Practice › Codeforces Solutions › Codeforces Round 849 (Div. 4) ›

CF 1791G1 - Teleporters (Easy Version)

We are placed on a line of integer points from 0 to n. At every position i from 1 to n, there is a teleporter that can be used exactly once, and using it sends us back to position 0. The cost of using the teleporter at i is a[i].

Practice › Codeforces Solutions › Codeforces Round 849 (Div. 4) ›

CF 1791E - Negatives and Positives

We are given an array of integers, which can be positive, negative, or zero, and we are allowed to perform a single operation any number of times: choose two adjacent elements and flip their signs simultaneously.

Practice › Codeforces Solutions › Codeforces Round 849 (Div. 4) ›

CF 1791B - Following Directions

Alperen starts at the origin (0,0) on a 2D grid. He is given a sequence of n moves, where each move shifts him one unit in one of the four cardinal directions: left, right, up, or down.

Practice › Codeforces Solutions › Codeforces Round 849 (Div. 4) ›

CF 1791C - Prepend and Append

We are given a binary string that is the final result of repeatedly applying a very specific operation. Each operation takes the current string and expands it by adding one character to the left end and one character to the right end, with the constraint that the two added…

Practice › Codeforces Solutions › Codeforces Round 849 (Div. 4) ›

CF 1791A - Codeforces Checking

We are given a very small decision problem repeated multiple times. Each test case provides a single lowercase English letter, and we must decide whether that letter belongs to a fixed reference string, namely “codeforces”.