algos1

#include<iostream>
#include<vector>
#include<limits.h>
#include<string>
#include<list>



class Graph
{
	int vertices;
	std::list<int>* adjlist;
	int* visited;
public:
	Graph(int v);
	void addEdge(int src, int dest);
	void displaylist();
	void bfs(int sv);
	void dfs(int sv);
	void tps(int sv);
	


};

Graph::Graph(int v)
{
	vertices = v;
	adjlist = new std::list<int>[v];
	visited = new int[v] {0};
	
}

void Graph::addEdge(int src, int dest)
{
	adjlist[src].push_back(dest);
	
}

void Graph::displaylist()
{
	for (int i = 0; i < vertices; i++)
	{
		std::cout << i << " :";
		for (auto k : adjlist[i])
		{
			std::cout << " -->" << k;
		}
		std::cout << std::endl;

	}
}

void Graph::bfs(int sv)
{
	
	visited[sv] = 1;
	int current;// stores the dequeued node.

	std::list<int> queue;
	queue.push_front(sv);

	while (!queue.empty())
	{
		current = queue.front();
		visited[current] = 1;
		queue.pop_front();
		std::cout << current << " ";
		for (auto i : adjlist[current])
		{
			if (visited[i] != 1)
			{
				queue.push_back(i);
				visited[i] = 1;
			}
		}
	}

	delete[] visited;

}

void Graph::dfs(int sv)
{	
	visited[sv] = 1;
	std::cout << sv << " ";
	for (auto x : adjlist[sv])
	{
		if (visited[x] == 0)
		{
			visited[x] = 1;
			dfs(x);
		}
	}
}

void Graph::tps(int sv)
{

	int* start = new int[vertices] {0};


	std::list<int> tps;
	std::list<int> stack;
	stack.push_front(sv);
	start[sv] = 1;
	std::cout << sv << " ";
	int current;
	int t = 1; // traversal index.

	for (int i = 0; i < vertices; i++)
	{
		if (start[i] == 0 && stack.empty())
		{
			stack.push_front(i);
			start[i] = ++t;
		}

		int temp;
		while (!stack.empty())
		{
			current = stack.front();


			bool flag = true;
			for (auto x : adjlist[current])
			{
				if (start[x] == 0)
				{
					flag = false;
					std::cout << x << " ";
					start[x] = ++t;
					stack.push_front(x);
				}
			}

			if (flag)
			{
				tps.push_front(stack.front());
				stack.pop_front();

			}

		}
		//
	}

	std::cout << "\n";
	for (auto x : tps)
	{
		std::cout << x << " ";
	}
}
int main()
{
	Graph g(4);
	g.addEdge(0, 1);
	g.addEdge(0, 2);
	g.addEdge(1, 2);
	g.addEdge(2, 0);
	g.addEdge(2, 3);
	g.addEdge(3, 3);

	//g.displaylist();
	g.dfs(2);
	

	return 0;
}