Restructured folders, added topological order alg

This commit is contained in:
GregorSamsa42 2024-07-24 15:54:43 +02:00
parent 56a5b594e4
commit a2bc786543
5 changed files with 93 additions and 3 deletions

View file

@ -1,6 +1,6 @@
cmake_minimum_required(VERSION 3.10)
project(Kosaraju)
add_executable(Kosaraju
digraph.cpp
digraph.h
main.cpp)
../digraph.cpp
../digraph.h
main.cpp)

View file

@ -10,6 +10,11 @@ void Node::add_edge(int v)
neighbours.push_back(v);
}
int Node::outdeg() const
{
return neighbours.size();
}
Digraph::Digraph(size_t num_nodes) : nodes(num_nodes)
{
@ -30,6 +35,24 @@ bool Digraph::isEdge(int from, int to) const
return (std::find(adjList(from).begin(), adjList(from).end(), to) != adjList(from).end());
}
int Digraph::outdeg(int node_id) const
{
return nodes[node_id].outdeg();
}
std::vector<int> Digraph::indegrees() const
{
std::vector<int> indegs (num_nodes(),0);
for(int i = 0; i < num_nodes(); i++)
{
for (auto const& j: ((nodes[i]).neighbours))
{
indegs[j]++;
}
}
return indegs;
}
size_t Digraph::num_nodes() const
{
return nodes.size();

View file

@ -12,6 +12,7 @@ struct Node {
Node() = default;
Node(std::list<int> neighbours);
void add_edge(int v);
int outdeg() const;
};
class Digraph {
@ -22,6 +23,8 @@ public:
size_t num_nodes() const;
Digraph transpose() const;
bool isEdge(int from, int to) const;
int outdeg(int v) const;
std::vector<int> indegrees() const;
private:
std::vector<Node> nodes;

6
top_order/CMakeLists.txt Normal file
View file

@ -0,0 +1,6 @@
cmake_minimum_required(VERSION 3.10)
project(top_order)
add_executable(top_order
../digraph.cpp
../digraph.h
top_order.cpp)

58
top_order/top_order.cpp Normal file
View file

@ -0,0 +1,58 @@
// Kosarajus algorithm to find strongly connected components of a directed graph
// Authors: Georǵi Kocharyan, Maximilian Keßler
#include <iostream>
#include <cstdio>
#include <vector>
#include <stack>
#include "../digraph.h"
int main() {
int size = 10;
Digraph G(size);
G.add_edge(3,4);
// G.add_edge(4,3);
// G.add_edge(5,6);
G.add_edge(6,7);
G.add_edge(7,5);
// G.add_edge(7,3);
// G.add_edge(0,3);
// G.add_edge(3,0);
std::stack<int> zero_indegree;
std::vector<int> indegs = G.indegrees();
int amount = 0;
for(int i = 0; i < size; i++)
{
if (indegs[i] == 0)
{
zero_indegree.push(i);
amount++;
}
}
while(!zero_indegree.empty())
{
int node_id = zero_indegree.top();
zero_indegree.pop();
std::cout << node_id << ' ';
for(auto i: G.adjList(node_id))
{
if (indegs[i] = 1)
{
zero_indegree.push(i);
amount++;
}
indegs[i]--;
}
}
if (!(amount == size))
{
std::cout << '\n' << "The graph contains cycles and thus has no topological order." << std::endl;
}
return 0;
}