图的结构定义
图是由一个顶点集 V 和一个弧集 E构成的数据结构。
Graph = (V , E )
其中,E = {<v,w>| v,w∈V 且 P(v,w)} <v,w>表示从 v 到 w 的一条弧,并称 v 为弧尾,w 为弧头。谓词 P(v,w) 定义了弧 <v,w>的意义或信息。
由顶点集和边集构成的图称作无向图。
如果”弧”是有方向的,则称由顶点集和弧集构成的图为有向图。
邻接矩阵
定义:矩阵的元素为
有向图的邻接矩阵为非对称矩阵, 而无向图的邻接矩阵为对称矩阵;
//无向图的邻接矩阵 const int MAX_VERTS = 20; //顶点 template <typename Type> class Vertex { public: Vertex(const Type &_node = Type()) : node(_node) {} private: Type node; }; //图 template <typename Type> class Graph { public: Graph(); ~Graph(); void addVertex(const Type &vertex); void addEdge(int start, int end); void printMatrix(); private: Vertex<Type>* vertexList[MAX_VERTS]; int nVerts; int adjMatrix[MAX_VERTS][MAX_VERTS]; };
template <typename Type> Graph<Type>::Graph():nVerts(0) { for (int i = 0; i < MAX_VERTS; ++i) for (int j = 0; j < MAX_VERTS; ++j) adjMatrix[i][j] = 0; } template <typename Type> Graph<Type>::~Graph() { for (int i = 0; i < nVerts; ++i) delete vertexList[i]; }
template <typename Type> void Graph<Type>::addVertex(const Type &vertex) { vertexList[nVerts ++] = new Vertex<Type>(vertex); } template <typename Type> void Graph<Type>::addEdge(int start, int end) { //无向图 adjMatrix[start][end] = 1; adjMatrix[end][start] = 1; }
template <typename Type> void Graph<Type>::printMatrix() { for (int i = 0; i < nVerts; ++i) { for (int j = 0; j < nVerts; ++j) cout << adjMatrix[i][j] << ‘ ‘; cout << endl; } }
//测试代码 int main() { Graph<char> g; g.addVertex(‘A‘); //0 g.addVertex(‘B‘); //1 g.addVertex(‘C‘); //2 g.addVertex(‘D‘); //3 g.addVertex(‘E‘); //4 g.addEdge(0, 1); //A-B g.addEdge(0, 3); //A-D g.addEdge(1, 0); //B-A g.addEdge(1, 4); //B-E g.addEdge(2, 4); //C-E g.addEdge(3, 0); //D-A g.addEdge(3, 4); //D-E g.addEdge(4, 1); //E-B g.addEdge(4, 2); //E-C g.addEdge(4, 3); //E-D g.printMatrix(); return 0; }
邻接表
注意:在有向图的邻接表中不易找到指向该顶点的弧。
//无向图的邻接表 template <typename Type> class Graph { public: Graph(int _size = 10); ~Graph(); void addVertex(const Type &vertex); void addEdge(int start, int end); void printVertex(); void printAdjList(); private: Type *vertexList; list<int> *headNode; int size; int nVertex; };
template <typename Type> Graph<Type>::Graph(int _size):size(_size), nVertex(0) { vertexList = new Type[size]; headNode = new list<int>[size]; } template <typename Type> Graph<Type>::~Graph() { delete []vertexList; delete []headNode; }
template <typename Type> void Graph<Type>::addVertex(const Type &vertex) { vertexList[nVertex ++] = vertex; } template <typename Type> void Graph<Type>::addEdge(int start, int end) { headNode[start].push_back(end); }
template <typename Type> void Graph<Type>::printVertex() { cout << vertexList[0]; for (int i = 1; i < nVertex; ++i) cout << ‘ ‘ << vertexList[i]; cout << endl; } template <typename Type> void Graph<Type>::printAdjList() { for (int i = 0; i < nVertex; ++i) { cout << i; for (list<int>::iterator iter = headNode[i].begin(); iter != headNode[i].end(); ++iter) cout << " -> " << *iter; cout << endl; } }
//测试代码 int main() { Graph<char> g; g.addVertex(‘A‘); //0 g.addVertex(‘B‘); //1 g.addVertex(‘C‘); //2 g.addVertex(‘D‘); //3 g.addVertex(‘E‘); //4 g.printVertex(); g.addEdge(0, 1); //A-B g.addEdge(0, 3); //A-D g.addEdge(1, 0); //B-A g.addEdge(1, 4); //B-E g.addEdge(2, 4); //C-E g.addEdge(3, 0); //D-A g.addEdge(3, 4); //D-E g.addEdge(4, 1); //E-B g.addEdge(4, 2); //E-C g.addEdge(4, 3); //E-D g.printAdjList(); return 0; }
时间: 2024-10-10 00:07:48