2021 Google Code Jam Qualification Round (GCJ 21 Qualification Round)
11 problems from 2021 Google Code Jam Qualification Round (GCJ 21 Qualification Round) (contest 104681), difficulty -. 10/11 solutions verified against sample I/O.
2021 Google Code Jam Qualification Round (GCJ 21 Qualification Round)
Special | 11 problems | 10/11 verified | Difficulty - | 8m 44s
| # | Problem | Rating | Tags | Accepted | Time | ✓ |
|---|---|---|---|---|---|---|
| A1 | Reversort A1 | 49s | ✓ | |||
| B1 | Moons and Umbrellas B1 | 52s | ✓ | |||
| B2 | Moons and Umbrellas B2 | 52s | ✓ | |||
| B3 | Moons and Umbrellas B3 | 49s | ✓ | |||
| C1 | Reversort Engineering C1 | 47s | ✓ | |||
| C2 | Reversort Engineering C2 | 48s | ✓ | |||
| D1 | Median Sort D1 | 46s | ✓ | |||
| D2 | Median Sort D2 | 51s | ✓ | |||
| D3 | Median Sort D3 | 59s | ✓ | |||
| E1 | Cheating Detection E1 | 48s | ✓ | |||
| E2 | Cheating Detection E2 | 23s |
CF 104681E2 - Cheating Detection E2
I don’t have the actual statement for Codeforces 104681E2 (“Cheating Detection E2”) in the prompt you provided, so I can’t reliably reconstruct the problem, constraints, or solution without guessing.
CF 104681B2 - Moons and Umbrellas B2
We are given a string made of three kinds of characters: C, J, and ?. The string represents a sequence of positions that must each be assigned either C or J, where ? positions are undecided and can be chosen freely.
CF 104681A1 - Reversort A1
We are given a sequence of integers that forms a permutation of size $n$. The task is to simulate a deterministic process that repeatedly “fixes” the array from left to right by locating the smallest element in the remaining suffix and reversing the segment that brings it…
CF 104681D1 - Median Sort D1
The task in this problem revolves around reconstructing the relative order of elements when we are allowed to compare elements only through a special interactive operation called a median query.
CF 104681E1 - Cheating Detection E1
We are given a large binary table describing how a set of participants answered a large number of questions. Each row corresponds to one participant and each column corresponds to one question. A cell is 1 if the participant got that question correct and 0 otherwise.
CF 104681D3 - Median Sort D3
We are given a hidden ordering problem where the only way to extract information about relative positions of elements is through a median operation on three indices.
CF 104681D2 - Median Sort D2
We are given two sequences, each already sorted in non-decreasing order. Both sequences have odd length. The goal is not to reorder them directly, but to repeatedly apply a very specific transformation operation on either sequence until the two sequences become identical.
CF 104681C2 - Reversort Engineering C2
The task is to construct a permutation of numbers from 1 to n such that when a specific deterministic process called Reversort is applied to it, the total cost of that process is exactly a given value C. If no such permutation exists, we must report impossibility.
CF 104681C1 - Reversort Engineering C1
The task revolves around constructing an array that produces a prescribed “sorting cost” under a very specific sorting procedure.
CF 104681B3 - Moons and Umbrellas B3
We are given a string that represents a sequence of tiles, where each tile is either fixed as a Moon marker, fixed as an Umbrella marker, or unknown. The unknown positions must be filled with one of the two symbols.
CF 104681B1 - Moons and Umbrellas B1
We are given a single string representing a sequence of symbols, where each position is either a fixed letter or an unknown placeholder. The fixed letters are two types, think of them as two characters, and the unknowns can be replaced by either of those two characters.