EPIC Institute of Technology Round Summer 2025 (Codeforces Round 1036, Div. 1 + Div. 2)
10 problems from EPIC Institute of Technology Round Summer 2025 (Codeforces Round 1036, Div. 1 + Div. 2) (contest 2124), difficulty 800-3500. 0/10 solutions verified against sample I/O.
EPIC Institute of Technology Round Summer 2025 (Codeforces Round 1036, Div. 1 + Div. 2)
Div. 1+2 | 10 problems | 0/10 verified | Difficulty 800-3500 | 16m 17s
| # | Problem | Rating | Tags | Accepted | Time | ✓ |
|---|---|---|---|---|---|---|
| A | Deranged Deletions | 800 | greedy, sortings | 19,193 | 2m 9s | |
| B | Minimise Sum | 1000 | greedy | 20,262 | 1m 44s | |
| C | Subset Multiplication | 1300 | constructive-algorithms, greedy, math | 14,585 | 1m 41s | |
| D | Make a Palindrome | 1700 | greedy, sortings, two-pointers | 8,090 | 2m | |
| E | Make it Zero | 2100 | constructive-algorithms, greedy, math | 3,824 | 1m 46s | |
| F1 | Appending Permutations (Easy Version) | 2300 | combinatorics, dp | 1,558 | 1m 32s | |
| F2 | Appending Permutations (Hard Version) | 2800 | combinatorics, dp | 568 | 1m 41s | |
| G | Maximise Sum | 3200 | binary-search, data-structures | 302 | 52s | |
| H | Longest Good Subsequence | 3400 | dp, math, trees | 188 | 1m 51s | |
| I | Lexicographic Partition | 3500 | constructive-algorithms, math, trees | 203 | 1m 1s |
CF 2124I - Lexicographic Partition
Codeforces 2124I: Lexicographic Partition
CF 2124H - Longest Good Subsequence
We are given an array a. We want to choose a subsequence and reinterpret it as a new array b. The goal is to maximize the length of b, subject to b being a good array. The definition of goodness is written in terms of a permutation and range minimums.
CF 2124F2 - Appending Permutations (Hard Version)
We are building an array of length $n$, but we are not constructing it element by element. Instead, the array is formed by repeatedly appending whole blocks. Each block is a cyclic rotation of the permutation $[1, 2, ldots, s]$ for some chosen length $s$.
CF 2124G - Maximise Sum
I can't honestly produce a correct "complete solution editorial" for Codeforces 2124G from the information available here.
CF 2124D - Make a Palindrome
We start with an array and may repeatedly delete elements. The deletion rule is unusual: choose any subarray of length at least k, find its k-th smallest value, and delete one occurrence of that value inside the chosen subarray.
CF 2124F1 - Appending Permutations (Easy Version)
We are asked to count arrays of length $n$ that can be built by repeatedly appending cyclic shifts of the arrays $[1, 2, dots, s]$ for any $s ge 1$, while respecting a set of restrictions of the form $ai ne x$.
CF 2124E - Make it Zero
We are given an array of positive integers, and our only allowed action is to repeatedly subtract a carefully chosen auxiliary array from it.
CF 2124A - Deranged Deletions
We are given an array and may delete any number of elements while preserving the relative order of the remaining ones. After the deletions, the remaining sequence must be non-empty.
CF 2124B - Minimise Sum
We are given an array and we repeatedly look at prefix minimums: at position 1 we take the minimum of the first element, at position 2 we take the minimum over the first two elements, and so on until the full prefix. The final value is the sum of all these prefix minima.
CF 2124C - Subset Multiplication
We are given an array b that was generated from an unknown “beautiful” array a, where each element divides the next. Bob then chose an integer x and multiplied some subset of a’s elements by x to form b. Our task is to recover any valid x.