Codeforces Round 454 (Div. 1, based on Technocup 2018 Elimination Round 4)
Solutions for Codeforces Round 454 (Div. 1, based on Technocup 2018 Elimination Round 4) (contest 906). 3/5 problems verified against sample I/O. Difficulty range: 1600-3300.
Codeforces Round 454 (Div. 1, based on Technocup 2018 Elimination Round 4)
Type: Div. 1 | Problems: 5 | Verified: 3/5 | Rating range: 1600-3300 | Time: 38m 39s
| Problem | Name | Rating | Tags | Solve Time | Verified |
|---|---|---|---|---|---|
| A | Shockers | 1600 | implementation, strings | 5m 30s | ✓ |
| B | Seating of Students | 2200 | brute-force, constructive-algorithms, math | 6m 9s | ✗ |
| C | Party | 2400 | bitmasks, brute-force, dp | 7m 24s | ✓ |
| D | Power Tower | 2700 | chinese-remainder-theorem, math, number-theory | 14m 47s | ✓ |
| E | Reverses | 3300 | dp, string-suffix-structures, strings | 4m 49s | ✗ |
CF 906D - Power Tower
We are asked to compute a "power tower" modulo a given number. Conceptually, imagine a sequence of rocks, each with a positive integer power.
CF 906E - Reverses
We are given two strings of equal length. The first string, s, is the original string. The second string, t, is obtained after several pairwise disjoint substrings of s were reversed. The hurricane has already performed those reversals and produced t.
CF 906C - Party
We have a connected friendship graph. Choosing a vertex means that all of its neighbors become pairwise adjacent. In graph theory language, we are allowed to pick a vertex and turn its open neighborhood into a clique.
CF 906B - Seating of Students
We are asked to rearrange students in a classroom so that no two students who were neighbors in the original seating remain neighbors in the new arrangement. The classroom is an n×m grid, and the students are numbered sequentially from 1 to n·m in row-major order.
CF 906A - Shockers
Valentin is playing a game where a single unknown letter has been chosen, and every time he pronounces a word containing that letter, he gets shocked. He can also make guesses about the letter, and incorrect guesses result in shocks.