Problem B: Summation Game This problem involves a game between two players, Alice and Bob, operating on an array of integers. Alice aims to maximize the final sum of the array elements, while Bob aims to minimize it. Alice moves first by removing up to k elements from the array. Subsequently, Bob se...
Problem A Given three integers (x), (y), and (n), construct a sequence (a) of length (n) satisfying: (a_1 = x), (a_n = y). Sequence (a) is strictly increasing. The differences (b_i = a_{i+1} - a_i) form a strictly decreasing sequence. Start by defining the array with (a_1 = x) and (a_n = y). The key...
A. Binary Array Game Given a binary array, two players take turns selecting a segment [l,r] where lSolution: The key observation is that x=0 can only be produced when the entire segment consists of 1s. This makes 0 significantly harder to obtain than 1. Consider the second player's perspective: if t...
A - Increment or Smash Strategy: Direct simulation. Every element that is not the global maximum will undergo a reset to zero followed by an increment, contributing exactly two steps to the total. However, identical values only incur this penalty once. The global maximum avoids the reset step altoge...
Problem A: The Man who became a God For a sequence (a) of length (n), define the cost of a segment ([l, r]) as (f(l, r) = \sum_{i=l}^{r-1} |a_i - a_{i+1}|). We need to partition the entire sequence into (k) contiguous segments to maximize the sum of segment costs. The total cost of the whole sequenc...
A. Shift Sort Given a binary string s of length n, you can perform the following operation any number of times: choose three indices 1 ≤ i < j < k ≤ n and cyclically shift the values s_i, s_j, s_k to the left or to the right. The goal is to find the minimum number of operations required to sor...
Problem A Each participant can compete in at most two consecutive rounds. This implies that the observer of the first round follows a repeating pattern: observe → compete → compete. Therefore, the k-th round involves the initial observer if and only if $ k \mod 3 = 1 $. Problem B Let $ S = \frac{n(n...
Virtual participation in a Div. 3 round can be a great mood booster. This article covers all problems from that contest, providing solutions and code. A - Divisibility Problem Straightforward implementation. #include<bits/stdc++.h> using namespace std; void mian(){ int a,b; cin>>a>>...
After everyone else in the computer lab had many orange-rated handles, I finally achieved orange with my main account (apparently, I'm still quite weak). I'll write a blog post to record the experience. My counting skills are very poor. In the last 5 minutes of the contest, I hastily came up with a...