Graph Algorithms: Implementation& DFS& Strong Component& BFS & Dijkstra & Bellman Ford

#include<iostream>#include<vector>#include<string>#include<queue>#include <algorithm>using namespace::std;class Node;class Edge{public:Edge(Node* start, Node* end, int _cost = 0):from(start),to(end),cost(_cost){}Node * getFromNode(){return from;}Node * getToNode(){return to;}int getCost(){return cost;}private:Node * from;Node * to;int cost;};class Node{public:Node(string name):pre(0),post(0),nodeName(name),visit(0),dist(INT_MAX)   {}~Node(){for(int i = 0; i < adjList.size(); i++){delete adjList[i];}adjList.clear();}void showList(){cout<<nodeName<<": ";for(int i = 0; i < adjList.size(); i++){cout<<adjList[i]->getToNode()->getName()<<" ";}cout<<endl;}void addAnode(Node* newNode, int cost){Edge *newEdge = new Edge(this, newNode, cost);adjList.push_back(newEdge);}void deleteAnode(string name){for(int i = 0; i < adjList.size(); i++){if(name == adjList[i]->getToNode()->getName()){delete adjList[i];adjList.erase(adjList.begin() + i);}}}string getName(){return nodeName;}int getPre(){return pre;}void setPre(int _pre){pre = _pre;}int getPost(){return post;}void setPost(int _post){post = _post;}bool getStatus(){return visit;}void setStatus(bool _visit){visit = _visit;}void setDist(int _dist){dist = _dist;}int getDist(){return dist;}vector<Edge*>& getAdjList(){return adjList;}private:string nodeName;vector<Edge*> adjList;int pre;int post;bool visit;int dist;};class Graph{public:Graph():clock(1){}Graph(Graph * inputGraph){for(int i = 0; i < inputGraph->getList().size(); i++){Node* node = new Node(inputGraph->getList()[i]->getName());nodeList.push_back(node);}clock = 1;}~Graph(){for(int i = 0; i < nodeList.size(); i++){delete nodeList[i];}nodeList.clear();}void resetClock(){clock = 0;}void clearVisit(){for(int i = 0; i < nodeList.size(); i++){nodeList[i]->setStatus(0);}}Node* searchNodeByName(string name){for(int i = 0; i < nodeList.size(); i++){if(nodeList[i]->getName() == name)return nodeList[i];}}void addNode(Node * node){nodeList.push_back(node);}void deleteNode(string name){Node * tmp = getNodeByName(name);int pos;for(int i = 0; i < nodeList.size(); i++){nodeList[i]->deleteAnode(name);if(nodeList[i]->getName() == name){pos = i;}}nodeList[pos]->getAdjList().clear();delete nodeList[pos];nodeList.erase(nodeList.begin() + pos);}void display(){for(int i = 0; i < nodeList.size(); i++){//cout<<nodeList[i]->getPre()<<"  "<<nodeList[i]->getPost()<<"  ";cout<<nodeList[i]->getDist()<<"  ";nodeList[i]->showList();}}vector<Node* > & getList(){return nodeList;}Node* getNodeByName(string name){for(int i = 0; i < nodeList.size(); i++){if(nodeList[i]->getName() == name)return nodeList[i];}}void DFS(){for(int i = 0; i < nodeList.size(); i++){if(nodeList[i]->getStatus() == 0){explore(nodeList[i]);}}}void BFS(){queue<Node*> bfsQ;Node* tmp;bfsQ.push(nodeList[0]);nodeList[0]->setDist(0);while(bfsQ.size() != 0){tmp = bfsQ.front();bfsQ.pop();for(int i = 0; i < tmp->getAdjList().size(); i++){if(tmp->getAdjList()[i]->getToNode()->getDist() == INT_MAX){tmp->getAdjList()[i]->getToNode()->setDist(tmp->getDist() + 1);bfsQ.push(tmp->getAdjList()[i]->getToNode());}}}}void Dijkstra(){vector<Node *> queue(nodeList);nodeList[0]->setDist(0);//queue.push_back(nodeList[0]);while(queue.size() != 0){sort//可以用lambda表达式, 定义匿名函数, 语法是  [] (参数表){ 实现 } 匿名函数会自动成为友元(queue.begin(), queue.end(), [](Node* node1, Node* node2){return(node1->getDist() < node2->getDist());});Node* tmp = queue.front();queue.erase(queue.begin());cout<<queue.size()<<endl;for(int i = 0; i < tmp->getAdjList().size(); i++){if(tmp->getAdjList()[i]->getToNode()->getDist() > tmp->getAdjList()[i]->getCost() + tmp->getDist())tmp->getAdjList()[i]->getToNode()->setDist(tmp->getAdjList()[i]->getCost() + tmp->getDist());//queue.push_back(tmp->getAdjList()[i]->getToNode());}}}void Bellman(){nodeList[0]->setDist(0);for(int j = 0; j < nodeList.size() - 1; j++)//bellman ford 算法关键点{//tmp = bellQ.front();for(int x = 0; x < nodeList.size(); x++){for(int i = 0; i < nodeList[x]->getAdjList().size(); i++){if(nodeList[x]->getAdjList()[i]->getToNode()->getDist() > nodeList[x]->getAdjList()[i]->getCost() + nodeList[x]->getDist())nodeList[x]->getAdjList()[i]->getToNode()->setDist(nodeList[x]->getAdjList()[i]->getCost() + nodeList[x]->getDist());}}}}Graph* revese(){Graph* newGraph = new Graph(this);for(int i = 0; i < nodeList.size(); i++){for(int j = 0; j < nodeList[i]->getAdjList().size(); j++){newGraph->getNodeByName(nodeList[i]->getAdjList()[j]->getToNode()->getName())->addAnode(newGraph->getNodeByName(nodeList[i]->getName()),0);}}return newGraph;}void strong_component(){Graph * reverse_graph = new Graph;reverse_graph = this->revese();reverse_graph->DFS();for(int i = 0; i < reverse_graph->getList().size() - 1; i++){for(int j = i + 1; j < reverse_graph->getList().size(); j++){if(reverse_graph->getList()[i]->getPost() > reverse_graph->getList()[j]->getPost()){Node * tmp;tmp = reverse_graph->getList()[i];reverse_graph->getList()[i] = reverse_graph->getList()[j];reverse_graph->getList()[j] = tmp;}}}while(reverse_graph->getList().size() > 0){this->explore(getNodeByName(reverse_graph->getList().back()->getName()));//reverse_graph->getList().pop_back();for(int i = 0; i < nodeList.size(); i++){if(nodeList[i]->getStatus() == 1){cout<<nodeList[i]->getName()<<"  ";//reverse_graph->display();reverse_graph->deleteNode(nodeList[i]->getName());this->deleteNode(nodeList[i]->getName());i--;}}cout<<endl;this->clearVisit();}delete reverse_graph;}private:vector<Node* > nodeList;int clock;void explore(Node* node){node->setStatus(1);node->setPre(clock);clock++;vector<Edge*> adjList = node->getAdjList();for(int i = 0; i < adjList.size(); i++){if(adjList[i]->getToNode()->getStatus() == 0){explore(adjList[i]->getToNode());}}node->setPost(clock);clock++;}};Graph* createGraph(){/* Strongly connected components algorithmNode* node_A = new Node("A");Node* node_B = new Node("B");Node* node_C = new Node("C");Node* node_D = new Node("D");Node* node_E = new Node("E");Node* node_F = new Node("F");Node* node_G = new Node("G");Node* node_H = new Node("H");Node* node_I = new Node("I");Node* node_J = new Node("J");Node* node_K = new Node("K");Node* node_L = new Node("L");node_B->addAnode(node_A, 0);node_B->addAnode(node_E, 0);node_C->addAnode(node_B, 0);node_C->addAnode(node_F, 0);node_D->addAnode(node_B, 0);node_E->addAnode(node_B, 0);node_F->addAnode(node_C, 0);node_F->addAnode(node_E, 0);node_H->addAnode(node_F, 0);node_H->addAnode(node_G, 0);node_G->addAnode(node_E, 0);node_G->addAnode(node_I, 0);node_I->addAnode(node_J, 0);node_J->addAnode(node_G, 0);node_J->addAnode(node_L, 0);node_K->addAnode(node_H, 0);node_L->addAnode(node_K, 0);Graph* graph = new Graph();graph->addNode(node_A);graph->addNode(node_B);graph->addNode(node_C);graph->addNode(node_D);graph->addNode(node_E);graph->addNode(node_F);graph->addNode(node_G);graph->addNode(node_H);graph->addNode(node_I);graph->addNode(node_J);graph->addNode(node_K);graph->addNode(node_L);return graph;*/Node* node_A = new Node("A");Node* node_B = new Node("B");Node* node_C = new Node("C");Node* node_D = new Node("D");Node* node_E = new Node("E");node_A->addAnode(node_B, 6);node_A->addAnode(node_D, 7);node_B->addAnode(node_C, 5);node_B->addAnode(node_D, 8);node_B->addAnode(node_E, -4);node_C->addAnode(node_B, -2);node_D->addAnode(node_C, -3);node_D->addAnode(node_E, 9);node_E->addAnode(node_C, 7);node_E->addAnode(node_A, 2);Graph* graph = new Graph();graph->addNode(node_A);graph->addNode(node_B);graph->addNode(node_C);graph->addNode(node_D);graph->addNode(node_E);return graph;}void test(string * name){string * tmp = name;delete tmp;}int main(){/*vector<string *> test;string* aa = new string("test");test.push_back(aa);delete test[0];*/Graph * graph = createGraph();//Graph * reverse_graph = graph->revese();//graph->DFS();graph->display();//graph->deleteNode("B");//graph->BFS();//graph->Dijkstra();graph->Bellman();graph->display();//graph->display();//cout<<"reverse graph: "<<endl;//reverse_graph->DFS();//reverse_graph->display();//reverse_graph->strong_component();delete graph;//delete reverse_graph;}