AtCoder Beginner Contest 012 - Problem Solutions
A - Swapping Two Integers Read two integers, swap their values, and output them on separate lines.
B - Time Conversion Given N seconds where 0 ≤ N < 86400, convert it to 24-hour time format hh:mm:ss.
The conversion formula using modular arithmetic: [N \equiv a_0 \times 3600 + a_1 \times 60 + a_2 \times 1 \pmod{86400}]
Calculate hours, minute ...
Posted on Sat, 19 Sep 2026 16:13:54 +0000 by Ryokotsusai
Essential Graph Algorithms for Programming Contests
Dikjstra's Algorithm (Adjacency Matrix)
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int MAX_NODES = 510;
int node_count, edge_count;
int graph[MAX_NODES][MAX_NODES];
int min_distance[MAX_NODES];
bool visited[MAX_NODES];
int dijkstra_shortest_path() {
memset(min_distance, 0x3f, s ...
Posted on Fri, 18 Sep 2026 16:11:15 +0000 by sledgeweb
Calculating Network Delay Time with Dijkstra and Floyd-Warshall Algorithms
Dijkstra's Algorithm ApproachDijkstra's algorithm is suitable for finding the shortest paths from a single source node to all other nodes in a weighted graph with non-negative weights. For the network delay problem, we aim to determine the maximum shortest-path distance from the source node k to every other node. If any node remains unreachable ...
Posted on Mon, 07 Sep 2026 16:54:29 +0000 by mindfield
Algorithmic Problem Solving: Simulations, Matrix Calculations, and Graph Traversal
Analyzing Core Algorithmic Challenges
This document explores a series of computational tasks ranging from basic arithmetic simulations to complex graph theory applications. Each segment presents a unique logic puzzle requiring precise implementation.
Basic Output and Division Logic
The initial challenge requires generating a fixed motivational ...
Posted on Sun, 23 Aug 2026 16:35:55 +0000 by simplyi
Transitive Closure and Bitset Optimization for Partial Order Completion
Problem
Luogu P2881
Given \(n\) numbers and \(m\) relations of the form \(a > b\), determine how many additional pairwise comparisons are needed to deduce the total order of all numbers.
Solution
Two approaches exist: Floyd‑Warshall and topological sort. This article focuses on the latter.
If no relations are given, we need to check every pa ...
Posted on Wed, 22 Jul 2026 16:44:38 +0000 by jviney
Floyd Algorithm and Its Practical Applications in Graph Problems
Understanding the Floyd-Warshall Algorithm
The Floyd-Warshall algorithm is a classic dynamic programming approach used to compute the shortest paths between all pairs of vertices in a weighted graph. It operates efficiently on dense graphs where the number of edges is close to the square of the number of vertices. With a time complexity of \\(O ...
Posted on Thu, 25 Jun 2026 16:42:24 +0000 by antwonw
Graph Theory: Multi-source and Single-source Shortest Path Algorithms
Shortest path problems in graph theory often rely on the concept of relaxation. Relaxation occurs when a path from node u to v can be shoretned by routing through an intermediate node k, i.e., if dist[u][v] > dist[u][k] + dist[k][v], we update dist[u][v] accordingly.
Floyd-Warshall Algorithm (All-Pairs Shortest Paths)
To compute shortest pat ...
Posted on Wed, 03 Jun 2026 18:20:34 +0000 by little_tris
All-Pairs Shortest Path Computation Using the Floyd-Warshall Method
The Floyd-Warshall algorithm solves the all-pairs shortest path problem in a weighted graph, handling both positive and negative edge weights (with no negative cycles). It uses dynamic programming to iteratively improve shortest path estimates between every pair of vertices.
Core Principal
Define dist[i][j][k] as the shortest distance from node ...
Posted on Fri, 15 May 2026 09:39:48 +0000 by Rovas
Finding the Most Popular Person by Gender Using Floyd-Warshall Algorithm
Problem Analysis
Given N people with known gender (F for female, M for male), each person provides direct distance measurements to their friends. The distance between any two people is the minimum possible distance through any path of known relationships. For each person i, define their "opposite-gender distance" as the maximum value ...
Posted on Tue, 12 May 2026 20:41:56 +0000 by Salkcin