TheForces Round #21 (EDU-Forces)

7 problems from TheForces Round #21 (EDU-Forces) (contest 104502), difficulty -. 2/7 solutions verified against sample I/O.

7 items

TheForces Round #21 (EDU-Forces)

Special | 7 problems | 2/7 verified | Difficulty - | 14m 3s

# Problem Rating Tags Accepted Time ✓
A Interesting Index 2m 24s
B Magical Deletion 2m 24s ✓
C Legendary Drop 1m 45s ✓
D RPS Club Activity 1m 31s
E Binary Function 1m 31s
F Hacked! 3m 10s
G Revolving Sushi 1m 18s
Practice › Codeforces Solutions › TheForces Round #21 (EDU-Forces) ›

CF 104502F - Hacked!

Your current greedy idea (as reflected in the output like 6 -4 5) is effectively: - sort - take from one end - alternate signs That is not tied to the actual objective: maximizing the number of indices where consecutive prefix sums change sign or hit zero.
codeforces competitive-programming Jun 30, 2026
Practice › Codeforces Solutions › TheForces Round #21 (EDU-Forces) ›

CF 104502G - Revolving Sushi

We are given a circular conveyor with n plates, each holding some initial number of sushi pieces. Time advances in discrete seconds.
codeforces competitive-programming Jun 30, 2026
Practice › Codeforces Solutions › TheForces Round #21 (EDU-Forces) ›

CF 104502E - Binary Function

We are working with a function defined on integers through their binary representation. For any positive integer $x$, we look at its binary form without leading zeros. We then scan adjacent bits and count how many times the bit value changes from 0 to 1 or from 1 to 0.
codeforces competitive-programming Jun 30, 2026
Practice › Codeforces Solutions › TheForces Round #21 (EDU-Forces) ›

CF 104502D - RPS Club Activity

We are looking at a stochastic elimination process involving $n$ participants. In every round, each person independently chooses Rock, Paper, or Scissors according to fixed probabilities $a%$, $b%$, and $c%$.
codeforces competitive-programming Jun 30, 2026
Practice › Codeforces Solutions › TheForces Round #21 (EDU-Forces) ›

CF 104502A - Interesting Index

We are given an array of non-negative integers, and we are allowed to freely reorder the elements and also flip the sign of any subset of them. After doing this, we must output a final arrangement of signed numbers.
codeforces competitive-programming Jun 30, 2026
Practice › Codeforces Solutions › TheForces Round #21 (EDU-Forces) ›

CF 104502B - Magical Deletion

We are given a string and a fixed length $k$. We must remove exactly one contiguous substring of length $k$, and then join the remaining parts together.
codeforces competitive-programming Jun 30, 2026
Practice › Codeforces Solutions › TheForces Round #21 (EDU-Forces) ›

CF 104502C - Legendary Drop

We are simulating Teadose’s rating across a sequence of contests. Each contest has two attributes: a performance value and a division flag.
codeforces competitive-programming Jun 30, 2026