Freaks City

Problem Statement Given an integer \(M\), for any integer set \(S\), the "verification value" is defined as follows: From the set \(S\), extract \(M\) pairs of numbers (i.e., \(2M\) numbers, without reusing any element from the set; if there aren't enough numbers for \(M\) pairs, take as many as possible). The verification value is th ...

Problem Statement Given two strings s and t, and an integer k, determine if it's possible to extract two non-overlapping substrings of length k from s such that when concatenated, the resulting string contians t as a contiguous substring. Approach Problem Analysis: The solution involves checking if t can be formed by combining parts of two no ...

153. Minimum in Rotated Sorted Array Approach A rotated sorted array is formed by shifting elements from the end to the beginning. For instance, rotating [0,1,2,4,5,6,7] four times yields [4,5,6,7,0,1,2]. To find the minimum element efficiently, use binary search. Compare the middle element with the rightmost element: If arr[mid] < arr[righ ...

Problem A: Two Friends There are two possible scenarios: There exists a pair where person A's best friend is B, and B's best friend is A. In this case, just inviting these two individuals suffices. No such mutual friendship exists. If person A's best friend is B, and B's best friend is C, then inviting A, B, and C ensures both A and B attend. ...

A. Moving Chips A greedy approach is applicable. Chips can only move left to the nearest empty cell. Therefore, only the longest contiguous segment of 1s matters (denoted as s). The chips within this segment need to be consolidated. The minimal number of moves equals the number of 0s inside this segment. #include <iostream> #include <v ...

A. Curriculum Vitae The problem requires finding the longest subsequence where digit 1 is never followed by digit 0. This is equivalent to finding the longest non-decreasing subsequence in a binary sequence. An alternative approach uses prefix sums to count zeros and suffix sums to count ones. #include <bits/stdc++.h> #define endl '\n' # ...

Maximum Meetings Attendance Given a list of meetings where each meeting is represented as [start, end], determine the largest number of meetings you can attend if you can only be in one meeting per day and you may pick any day within the inclusive interval [start, end] to attend that meeting. Intuition The key observation is that we want to fin ...

[NOIP2004 Advanced Group] Merging Fruits / [USACO06NOV] Fence Repair G Problem Description In an orchard, Duoduo has already knocked down all the fruits and divided them into different piles according to their types. Duoduo decides to merge all the fruits into one pile. Each time, Duoduo can merge two piles together, and the effort consumed equ ...

Find the Champion in an Array Game Given a distinct-integer array arr and an integer k, simulate a game where the first two elements compete in each round. The larger value wins, stays at index 0, and the smaller one is moved to the end. The game ends as soon as any value wins k consecutive rounds; that value is the champion. Examples arr = [2 ...

Number Theory Primality Testing via Trial Division #include <iostream> using namespace std; bool isPrime(int num) { if (num < 2) return false; for (int d = 2; d <= num / d; ++d) if (num % d == 0) return false; return true; } int main() { int queries; cin >> queries; while (queries--) { ...