Codeforces Round 797 (Div. 3)

Solutions for Codeforces Round 797 (Div. 3) (contest 1690). 3/7 problems verified against sample I/O. Difficulty range: 800-2000.

7 items

Codeforces Round 797 (Div. 3)

Type: Div. 3 | Problems: 7 | Verified: 3/7 | Rating range: 800-2000 | Time: 20m 11s

Problem Name Rating Tags Solve Time Verified
A Print a Pedestal (Codeforces logo?) 800 constructive-algorithms, greedy 1m 49s ✗
B Array Decrements 800 greedy, implementation 2m 30s ✗
C Restoring the Duration of Tasks 800 data-structures, greedy, implementation 5m 52s ✗
D Black and White Stripe 1000 implementation, two-pointers 1m 24s ✓
E Price Maximization 1500 binary-search, greedy, math 2m ✓
F Shifting String 1700 graphs, math, number-theory 1m 51s ✓
G Count the Trains 2000 binary-search, data-structures, greedy 4m 45s ✗
Practice › Codeforces Solutions › Codeforces Round 797 (Div. 3) ›

CF 1690G - Count the Trains

Each carriage has its own maximum speed. When all carriages start moving, a carriage cannot move faster than any carriage in front of it, so its actual speed becomes the minimum value seen so far from the left.
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CF 1690C - Restoring the Duration of Tasks

We are given two increasing arrays. The array s contains the arrival time of each task. Task i becomes available at time s[i]. The array f contains the completion time of each task. Task i finishes exactly at time f[i]. Polycarp processes tasks in FIFO order.
codeforces competitive-programming data-structures greedy implementation Jun 9, 2026
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CF 1690F - Shifting String

We are given a string s of length n and a permutation p of the integers from 1 to n. Each permutation p defines a reordering operation: after one application, the character at position i in the new string moves to position p[i].
codeforces competitive-programming graphs math number-theory strings Jun 9, 2026
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CF 1690E - Price Maximization

We are given an even number of goods, each with a weight, and we need to pack them into pairs. The cost of a pair is calculated by taking the sum of its weights, dividing by a fixed number $k$, and rounding down to the nearest integer.
codeforces competitive-programming binary-search greedy math two-pointers Jun 9, 2026
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CF 1690D - Black and White Stripe

We are given a stripe of tiles, each either white or black, and the goal is to ensure that at least one segment of exactly k consecutive tiles is entirely black.
codeforces competitive-programming implementation two-pointers Jun 9, 2026
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CF 1690B - Array Decrements

We are given two arrays of non-negative integers, a and b, both of length n. The allowed operation is to simultaneously decrement all positive elements of a by one.
codeforces competitive-programming greedy implementation Jun 9, 2026
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CF 1690A - Print a Pedestal (Codeforces logo?)

We are given a number of identical building blocks and must split them into three stacks representing a podium. Each stack corresponds to a rank: third place, second place, and first place.
codeforces competitive-programming constructive-algorithms greedy Jun 9, 2026