GraphLibrary/Graph.cpp at main · PhoenixSmaug/GraphLibrary · GitHub

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#include<iostream>
#include<stdexcept>
#include<queue>
#include<stack>
#include"Graph.h"

std::ostream &operator<<(std::ostream& os, const Graph& graph) {
for (int i = 0; i < graph.adjList.size(); ++i) {
for (autoconst& j : graph.adjList[i]) { os << i << " -> " << j << std::endl; }
 }
return os;
}

Graph::Graph(int n) : adjList(std::vector<std::list<int>>(n)) { }

Graph::Graph(std::vector<std::pair<int, int>> edges) {
int max = 0;
for (int i = 0; i < edges.size(); ++i) {
if (edges[i].first < 0 || edges[i].second < 0) { throwstd::invalid_argument("negative value for vertex"); }
 max = (edges[i].first > max) ? edges[i].first : max;
 max = (edges[i].second > max) ? edges[i].second : max;
 }

this->adjList = std::vector<std::list<int>>(max + 1);
for (int i = 0; i < edges.size(); ++i) {
addEdge(edges[i]);
 }
}

boolGraph::existVertex(constint n) { return (n < this->adjList.size()); }

size_tGraph::addVertex() {
this->adjList.emplace_back(std::list<int>());
returnthis->adjList.size() - 1;
}

boolGraph::existEdge(constint b, constint e) {
return (this->edges.find({b, e}) != this->edges.end());
}

boolGraph::existEdge(const std::pair<int, int> edge) {
return (this->edges.find(edge) != this->edges.end());
}

voidGraph::addEdge(constint b, constint e) {
this->adjList[b].push_back(e);
this->edges.insert({b, e});
}

voidGraph::addEdge(const std::pair<int, int> edge) {
this->adjList[edge.first].push_back(edge.second);
this->edges.insert(edge);
}

boolGraph::removeEdge(constint b, constint e) {
this->adjList[b].remove(e);
returnthis->edges.erase({b, e});
}

boolGraph::removeEdge(const std::pair<int, int> edge) {
this->adjList[edge.first].remove(edge.second);
returnthis->edges.erase(edge);
}

voidGraph::turnUndirected() {
/*
 * Turn Undirected
 * - Complete directed graph to undirected graph
*/

for (int i = 0; i < this->adjList.size(); ++i) {
for (autoconst& j : this->adjList[i]) {
if (!this->existEdge(j, i)) {
addEdge(j, i);
 }
 }
 }
}

std::vector<bool> Graph::bfs(constint source) {
if (source >= this->adjList.size()) { throwstd::invalid_argument("node not in graph"); }
 std::queue<int> search;
 std::vector<bool> explored(this->adjList.size(), false);
 search.push(source);
 explored[source] = true;

while (!search.empty()) {
constint &vertex = search.front();
 search.pop();
for (autoconst& i : this->adjList[vertex]) {
if (!explored[i]) {
 explored[i] = true;
 search.push(i);
 }
 }
 }

return explored;
}

boolGraph::bfs(constint source, constint goal) {
if (source >= this->adjList.size() || goal >= this->adjList.size()) { throwstd::invalid_argument("node not in graph"); }
 std::queue<int> search;
 std::vector<bool> explored(this->adjList.size(), false);
 search.push(source);
 explored[source] = true;

while (!search.empty()) {
constint &vertex = search.front();
 search.pop();
if (vertex == goal) { returntrue; }
for (autoconst& i : this->adjList[vertex]) {
if (!explored[i]) {
 explored[i] = true;
 search.push(i);
 }
 }
 }

returnfalse;
}

std::vector<bool> Graph::dfs(constint source) {
if (source >= this->adjList.size()) { throwstd::invalid_argument("node not in graph"); }
 std::stack<int> search;
 std::vector<bool> explored(this->adjList.size(), false);
 search.push(source);

while (!search.empty()) {
constint &vertex = search.top();
 search.pop();
if (!explored[vertex]) {
 explored[vertex] = true;
for (autoconst& i : this->adjList[vertex]) {
 search.push(i);
 }
 }
 }

return explored;
}

boolGraph::dfs(constint source, constint goal) {
if (source >= this->adjList.size() || goal >= this->adjList.size()) { throwstd::invalid_argument("node not in graph"); }
 std::stack<int> search;
 std::vector<bool> explored(this->adjList.size(), false);
 search.push(source);

while (!search.empty()) {
constint &vertex = search.top();
 search.pop();
if (vertex == goal) { returntrue; }
if (!explored[vertex]) {
 explored[vertex] = true;
for (autoconst& i : this->adjList[vertex]) {
 search.push(i);
 }
 }
 }

returnfalse;
}

std::vector<int> Graph::topoSort() {
/*
 * Topological Sort
 * - Find topological sort of graph
 * - Returns empty vector if graph contains circles
 * - inspired by https://www.geeksforgeeks.org/topological-sorting-indegree-based-solution
*/

 std::vector<int> indegree(this->adjList.size());
for (int i = 0; i < this->adjList.size(); ++i) {
for (autoconst& j : this->adjList[i]) {
 ++indegree[j];
 }
 }
 std::queue<int> queue;
for (int i = 0; i < this->adjList.size(); ++i) {
if (indegree[i] == 0) {
 queue.push(i);
 }
 }

int count = 0;
 std::vector<int> order;
while (!queue.empty()) {
constint &vertex = queue.front();
 queue.pop();
 order.push_back(vertex);

for (autoconst& i : this->adjList[vertex]) {
 --indegree[i];
if (indegree[i] == 0) { queue.push(i); }
 }
 ++count;
 }
if (count != this->adjList.size()) { return std::vector<int>(); } // graph is not acyclic
return order;
}