基於C++ STL圖的鄰接表表示及深度、廣度搜索實現

#include <iostream>
#include <vector>
#include <set>

using namespace std;

#define MAX(a, b) ((a) > (b) ? (a) : (b) )

//定義圖的定點
typedef struct Vertex {
	int id;
	vector<int> connectors;    //存儲節點的後續鏈接頂點編號

	Vertex() : id(-1) {}
	Vertex(int nid) : id(nid) {}
} Vertex;

//定義Graph的鄰接表表示
typedef struct Graph {
	vector<Vertex> vertexs;   //存儲定點信息
	int nVertexs;		      //計數：鄰接數
	bool isDAG;               //標誌：是有向圖嗎

	Graph(int n, bool isDAG) : nVertexs(n), isDAG(isDAG) { vertexs.resize(n); }

	//向圖中添加邊
	bool addEdge(int id1, int id2) {
		if (!(MAX(id1, id2) < vertexs.size())) return false;

		if (isDAG) {
			vertexs[id1].connectors.push_back(id2);
		}
		else {
			vertexs[id1].connectors.push_back(id2);
			vertexs[id2].connectors.push_back(id1);
		}
		return true;
	}

	//廣度優先搜索
	vector<int> BFS(int start) {
		set<int> visited;
		vector<int> g, rst;
		g.push_back(start);
		visited.insert(start);
		while(g.size() > 0) {
			int id = g[0];			
			g.erase(g.begin());
			rst.push_back(id);
			for(int i = 0; i < vertexs[id].connectors.size(); i++) {
				int id1 = vertexs[id].connectors[i];
				if (visited.count(id1) == 0) {
					g.push_back(id1);
					visited.insert(id1);
				}
			}
		}
		return rst;
	}

	//深度優先搜索
	vector<int> DFS(int start) {
		set<int> visited;
		vector<int> g, rst;
		g.push_back(start);
		//cout << "push " << start << " ";
		visited.insert(start);
		rst.push_back(start);
		bool found;
		while(g.size() > 0) {
			int id = g[g.size()-1];			
			found = false;
			for(int i = 0; i < vertexs[id].connectors.size(); i++) {
				int id1 = vertexs[id].connectors[i];
				if (visited.count(id1) == 0) {
					g.push_back(id1);
					rst.push_back(id1);
					visited.insert(id1);
					//cout << "push " << id1 << " ";
					found = true;
					break;
				}
			}
			if (!found) {
				int id2 = g[g.size()-1];
				rst.push_back(-1 * id2);
				//cout << "pop " << id2 << " ";
				g.pop_back();
			}
		}
		//cout << endl;
		return rst;
	}
} Graph;

int main() {
	Graph g(8, false);
	g.addEdge(0, 1);
	g.addEdge(0, 3);
	g.addEdge(1, 2);
	g.addEdge(3, 4);
	g.addEdge(3, 5);
	g.addEdge(4, 5);
	g.addEdge(4, 6);    
	g.addEdge(5, 6);
	g.addEdge(5, 7);    
	g.addEdge(6, 7);
	vector<int> bv = g.BFS(0);
	cout << "寬度優先搜索節點順序：";
	for(int j = 0; j < bv.size(); j++)
	  cout << bv[j] << " ";
	cout << endl;

	cout << "深度優先搜索節點順序：";
	Graph g1(6, false);
	g1.addEdge(0, 1);
	g1.addEdge(0, 4);
	g1.addEdge(0, 5);
	g1.addEdge(1, 5);
	g1.addEdge(4, 5);
	g1.addEdge(5, 2);
	g1.addEdge(5, 3);
	g1.addEdge(2, 3);
	vector<int> route = g1.DFS(0);
	for(int i = 0; i < route.size(); i++)
	  cout << route[i] << " ";
	cout << endl;
	return 0;
}

運行：

$ ./a.out 
寬度優先搜索節點順序：0 1 3 2 4 5 6 7 
深度優先搜索節點順序：0 1 5 4 -4 2 3 -3 -2 -5 -1 0