Codeforces Beta Round 79 (Div. 1 Only)

Solutions for Codeforces Beta Round 79 (Div. 1 Only) (contest 101). 4/5 problems verified against sample I/O. Difficulty range: 1200-2500.

5 items

Codeforces Beta Round 79 (Div. 1 Only)

Type: Div. 1 | Problems: 5 | Verified: 4/5 | Rating range: 1200-2500 | Time: 11m 56s

Problem Name Rating Tags Solve Time Verified
A Homework 1200 greedy 2m 5s ✓
B Buses 1700 binary-search, data-structures, dp 1m 57s ✓
C Vectors 2000 implementation, math 2m 22s ✓
D Castle 2300 dp, greedy, probabilities 2m 6s ✓
E Candies and Stones 2500 divide-and-conquer, dp 3m 26s ✗
Practice › Codeforces Solutions › Codeforces Beta Round 79 (Div. 1 Only) ›

CF 101A - Homework

We start with a lowercase string and may delete at most k characters from it. The remaining characters must stay in their original order, since deleting characters creates a subsequence.
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Practice › Codeforces Solutions › Codeforces Beta Round 79 (Div. 1 Only) ›

CF 101B - Buses

We have bus stops placed on a line from 0 to n. Gerald starts at stop 0 and wants to reach stop n. Each bus is described by an interval [s, t]. Gerald may board that bus at any stop from s through t - 1, but once he rides it, he must stay on until stop t.
codeforces competitive-programming binary-search data-structures dp May 28, 2026
Practice › Codeforces Solutions › Codeforces Beta Round 79 (Div. 1 Only) ›

CF 101C - Vectors

We start with a vector A = (x1, y1) and want to transform it into another vector B = (x2, y2). Two operations are allowed. We may rotate the current vector by 90 degrees clockwise, and we may add vector C = (x3, y3) any number of times. The operations may be mixed in any order.
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Practice › Codeforces Solutions › Codeforces Beta Round 79 (Div. 1 Only) ›

CF 101D - Castle

We are given a weighted tree rooted at hall 1, where Gerald starts. The treasure is hidden uniformly at random in one of the other halls. Gerald only discovers the treasure when he first enters the correct hall.
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Practice › Codeforces Solutions › Codeforces Beta Round 79 (Div. 1 Only) ›

CF 101E - Candies and Stones

Gerald repeatedly removes either one candy or one stone. After every move, Mike looks at how many candies and stones Gerald has already eaten. If Gerald has eaten a candies and b stones so far, Mike awards $$f(a,b) = (xa + yb) bmod p$$ points.
codeforces competitive-programming divide-and-conquer dp May 28, 2026