The Inclusion-Exclusion Principle: Applications in Competitive Programming

The Inclusion-Exclusion Principle The Inclusion-Exclusion Principle is a fundamental concept in combinatorics that provides a method for calculating the size of the union of multiple sets. It addresses the problem of avoiding overcounting elements that belong to multiple sets by systematically accounting for intersections. Codeforces 547C: Mi ...

Posted on Tue, 12 May 2026 15:12:06 +0000 by aouriques

Preliminary solutions for AtCoder Beginner Contest 064

Problem A: Check multiples of 4 Given three digits a, b, c (most significant first), form the three-digit number n = 100*a + 10*b + c. Determine whether n is divisible by 4. int a, b, c; cin >> a >> b >> c; int n = a * 100 + b * 10 + c; cout << (n % 4 == 0 ? "YES" : "NO") << "\n"; Pro ...

Posted on Mon, 11 May 2026 07:02:20 +0000 by lostsoul111455

CCPC Qinhuangdao Contest: Problem Solutions and Code

Problem A. Is Your School the Kingdom of Construction I Approach The official solution provides a clear construction method. We need to generate exactly k coordinate pairs (x, y) where both coordinates are between 1 and n. First, we construct a base set of edges forming a connected structure. Then, if additional pairs are needed, we fill in the ...

Posted on Sun, 10 May 2026 20:13:05 +0000 by ragefu

Codeforces Round 4 Challenges

Codeforces Round 4 Challenges A-String Construction Challenge Output several 'you' strings and fill the rest with arbitrary characters #pragma GCC optimize(3) #include <bits/stdc++.h> #define endl '\n' #define int long long using namespace std; signed main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n,m; cin ...

Posted on Sun, 10 May 2026 20:01:07 +0000 by signs

Probability Calculation Strategy for Dice and Coin Scenarios

Problem Overview This problem involves calculating the winning probability in a game defined by two random processes: an N-sided die and a fair coin. The objective is to reach a specific threshold K starting from a value generated by the die roll. Game Mechanics Initialization: Roll an N-sided die. The outcome serves as the initial score, rang ...

Posted on Sun, 10 May 2026 18:48:19 +0000 by Roggan

Implementing Balanced Trees: Rotational vs Non-rotational Treaps

P6136 Enhanced Balanced Tree Template After struggling with rotational Treaps, I've concluded they're overly complex. FHQ Treaps offer a much cleaner implementation, with roughly half the code size. Rotational Treap Implementation Structure and data definitions: const int INF=1e18; struct TreeNode { int left, right; int value, priority; ...

Posted on Sun, 10 May 2026 18:15:42 +0000 by spaceknop

Solutions for ACGO Contest #13 Problems

T1 - Meteor Shower Era Approach Follow a direct simulation logic: Determine the first year the observer sees a meteor: (E + B) % 50. If this age exceeds the lifespan L, output 0. Otherwise, calculate the remaining years L - first_year and divide by the cycle length 50, adding 1 for the first sighting. C++ Implementation #include <bits/stdc ...

Posted on Sun, 10 May 2026 10:38:42 +0000 by zzman

Competitive Programming Problem Solutions: Basic Algorithms and Data Structures

Problem 1: Character Output Output each character of the string "I Love GPLT" on a separate line. #include <iostream> using namespace std; int main() { string msg = "I Love GPLT"; for (char c : msg) { cout << c << '\n'; } return 0; } Problem 2: Standard Weight Calculation Given a ...

Posted on Sat, 09 May 2026 19:24:39 +0000 by AndyEarley

Implementing Prim's Algorithm for Minimum Spanning Trees with Road Construction Problem Solution

Prim's Algorithm for Minimum Spanning Trees Prim's algorithm utilizes a distance array where dist[j] represents the shortest distance from node j to the current connected component. The process begins by selecting an arbitrary starting node and initializing distances to all other nodes. Algorithm Steps: Initialize all distances to infinity exc ...

Posted on Sat, 09 May 2026 19:21:43 +0000 by paulieo10

2016 CSP-J Preliminary Contest: Complete Problem Analysis and Solutions

Question 1 Which of the following software is NOT produced by Microsoft? A. PowerPoint B. Word C. Excel D. Acrobat Reader Answer: D Options A, B, and C are all part of Microsoft Office suite. Acrobat Reader is a PDF viewer developed by Adobe Systems. Question 2 To represent 256 different colors using binary encoding, what is the minimum number ...

Posted on Fri, 08 May 2026 17:15:03 +0000 by co.ador