Codeforces Round 833 (Div. 2)

Solutions for Codeforces Round 833 (Div. 2) (contest 1748). 2/6 problems verified against sample I/O. Difficulty range: 800-3000.

6 items

Codeforces Round 833 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 2/6 | Rating range: 800-3000 | Time: 13m 46s

Problem Name Rating Tags Solve Time Verified
A The Ultimate Square 800 math 3m 20s ✓
B Diverse Substrings 1400 brute-force, implementation, strings 1m 41s ✗
C Zero-Sum Prefixes 1600 brute-force, data-structures, dp 2m 40s ✓
D ConstructOR 2100 bitmasks, chinese-remainder-theorem, combinatorics 1m 28s ✗
E Yet Another Array Counting Problem 2300 binary-search, data-structures, divide-and-conquer 2m 23s ✗
F Circular Xor Reversal 3000 bitmasks, constructive-algorithms 2m 14s ✗
Practice › Codeforces Solutions › Codeforces Round 833 (Div. 2) ›

CF 1748F - Circular Xor Reversal

Let the triangle be $ABC$, let $H$ be its orthocenter, and let $omega$ be its incircle with center $I$ and radius $r$. The beetles move along the altitudes. Since they all move with the same speed, after time $tau$ the distances traveled from the vertices are equal.
codeforces competitive-programming bitmasks constructive-algorithms Jun 9, 2026
Practice › Codeforces Solutions › Codeforces Round 833 (Div. 2) ›

CF 1748E - Yet Another Array Counting Problem

We are asked to count the number of arrays b of length n that satisfy a very particular property derived from an array a. Each element bi must be between 1 and m. For any subarray [l, r], the leftmost maximum in b[l..r] must be at the same position as in a[l..r].
codeforces competitive-programming binary-search data-structures divide-and-conquer dp flows math trees Jun 9, 2026
Practice › Codeforces Solutions › Codeforces Round 833 (Div. 2) ›

CF 1748A - The Ultimate Square

We are given a sequence of rectangular wooden blocks. The i-th block always has height 1, and its length grows slowly with i according to the rule ⌈i/2⌉.
codeforces competitive-programming math Jun 9, 2026
Practice › Codeforces Solutions › Codeforces Round 833 (Div. 2) ›

CF 1748D - ConstructOR

Let the triangle be $ABC$, let $H$ be its orthocenter, and let $omega$ be its incircle with center $I$ and radius $r$. The beetles move along the altitudes. Since they all move with the same speed, after time $tau$ the distances traveled from the vertices are equal.
codeforces competitive-programming bitmasks chinese-remainder-theorem combinatorics constructive-algorithms math number-theory Jun 9, 2026
Practice › Codeforces Solutions › Codeforces Round 833 (Div. 2) ›

CF 1748C - Zero-Sum Prefixes

We are given a sequence of integers, and we care about how often its prefix sums hit zero. A prefix sum at position i is the sum of the first i elements, and we score the array by counting how many of these prefix sums are exactly zero.
codeforces competitive-programming brute-force data-structures dp greedy implementation Jun 9, 2026
Practice › Codeforces Solutions › Codeforces Round 833 (Div. 2) ›

CF 1748B - Diverse Substrings

Let the triangle be $ABC$, let $H$ be its orthocenter, and let $omega$ be its incircle with center $I$ and radius $r$. The beetles move along the altitudes. Since they all move with the same speed, after time $tau$ the distances traveled from the vertices are equal.
codeforces competitive-programming brute-force implementation strings Jun 9, 2026