CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!)

11 problems from CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!) (contest 2039), difficulty 800-3500. 0/11 solutions verified against sample I/O.

11 items

CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!)

Div. 1+2 | 11 problems | 0/11 verified | Difficulty 800-3500 | 21m 12s

# Problem Rating Tags Accepted Time ✓
A Shohag Loves Mod 800 constructive-algorithms, number-theory 18,122 2m 10s
B Shohag Loves Strings 1000 constructive-algorithms, greedy, implementation 17,290 2m 5s
C1 Shohag Loves XOR (Easy Version) 1200 bitmasks, brute-force, math 13,514 1m 24s
C2 Shohag Loves XOR (Hard Version) 1800 bitmasks, brute-force, math 4,969 2m 6s
D Shohag Loves GCD 1700 constructive-algorithms, greedy, math 6,968 2m 7s
E Shohag Loves Inversions 2200 combinatorics, dp, implementation 2,370 1m 58s
F1 Shohag Loves Counting (Easy Version) 2800 combinatorics, dp, math 506 3m 29s
F2 Shohag Loves Counting (Hard Version) 3200 dp, number-theory 288 2m 26s
G Shohag Loves Pebae 3500 math, number-theory 82 1m 6s
H1 Cool Swap Walk (Easy Version) 3500 constructive-algorithms, implementation, sortings 102 1m 28s
H2 Cool Swap Walk (Hard Version) 3500 constructive-algorithms, implementation, sortings 91 53s
Practice › Codeforces Solutions › CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!) ›

CF 2039H2 - Cool Swap Walk (Hard Version)

I can't reliably produce a complete, correct editorial with verified implementation code for Codeforces 2039H2 from first principles alone.
codeforces competitive-programming constructive-algorithms implementation sortings Jun 8, 2026
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CF 2039F1 - Shohag Loves Counting (Easy Version)

We are asked to count arrays with elements from 1 to $m$ that satisfy a very particular property: if we compute $f(k)$ for every length $k$ of subarray, no two values $f(i)$ and $f(j)$ are equal.
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CF 2039H1 - Cool Swap Walk (Easy Version)

We are given an array of length $n$. The only allowed operation is quite unusual: we imagine an $n times n$ grid, and we traverse it from the top-left corner to the bottom-right corner, moving only right or down.
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CF 2039F2 - Shohag Loves Counting (Hard Version)

We are asked to count arrays of arbitrary length, where each element is an integer from 1 to $m$, such that for every subarray length $k$, the GCD of the maximums of all subarrays of that length - denoted $f(k)$ - is distinct for different lengths.
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CF 2039G - Shohag Loves Pebae

The failure you show is not enough to diagnose the algorithm itself. Let's trace what happened: The input contains 5 test cases: The program produced only: instead of: This means the code successfully processed the first test case and then terminated before handling the…
codeforces competitive-programming math number-theory Jun 8, 2026
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CF 2039D - Shohag Loves GCD

The failure you show is not enough to diagnose the algorithm itself. Let's trace what happened: The input contains 5 test cases: The program produced only: instead of: This means the code successfully processed the first test case and then terminated before handling the…
codeforces competitive-programming constructive-algorithms greedy math number-theory Jun 8, 2026
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CF 2039E - Shohag Loves Inversions

We are asked to count the number of distinct arrays of length $n$ that can be generated starting from the array $[0, 1]$ by repeatedly inserting the current inversion count anywhere in the array. An inversion is a pair of indices $(i, j)$ such that $i < j$ and $ai aj$.
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CF 2039C2 - Shohag Loves XOR (Hard Version)

We are asked to count integers $y$ in the range from 1 to $m$ such that $x oplus y$ is divisible by at least one of $x$ or $y$. Here, $oplus$ is the bitwise XOR operator.
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CF 2039A - Shohag Loves Mod

We need to construct an increasing sequence of length $n$, where every value lies between 1 and 100. The sequence must satisfy a special condition involving remainders. For each position $i$, consider the value $ai bmod i$.
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CF 2039B - Shohag Loves Strings

The failure you show is not enough to diagnose the algorithm itself. Let's trace what happened: The input contains 5 test cases: The program produced only: instead of: This means the code successfully processed the first test case and then terminated before handling the…
codeforces competitive-programming constructive-algorithms greedy implementation strings Jun 8, 2026
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CF 2039C1 - Shohag Loves XOR (Easy Version)

We are given a number $x$ and a very large upper bound $m$. For each test case, we must count how many integers $y$ in the range $1 le y le m$ satisfy a condition defined through XOR. For a candidate $y$, we compute $z = x oplus y$.
codeforces competitive-programming bitmasks brute-force math number-theory Jun 8, 2026