有向图（网）、无向图（网）的构造以及遍历

构造图采用的是邻接表的方法，然后采用深度和广度优先进行遍历。（博主第一次写构造方法的时候花了很久写的很冗杂，虽然也实现了，但是感觉到处都在打补丁，拼拼凑凑写出来的，后来用了一分钟重写了一个，秒通过！！！欲哭无泪啊~原因主要是因为不同的输入格式导致的，以后些其他代码的时候要慎重考虑输入的格式问题）

下面贴代码！

根据书上的伪代码，写出定义的结构

const int MAX_VERTEX_NUM = 20;bool visited[MAX_VERTEX_NUM];    //遍历访问标志typedef struct ArcNode{int adjvex;    //该弧所指向的顶点的位置struct ArcNode *nextarc;    //指向下一条弧（边）的指针int weight;    //该弧（边）的权值}ArcNode;typedef struct VNode{char data;    //顶点信息ArcNode *firstarc;    //指向第一条依附该顶点的弧（边）的指针}VNode,AdjList[MAX_VERTEX_NUM];typedef struct{AdjList vertices;    int vexnum, arcnum;    //图的当前顶点数和弧（边）数int kind;}ALGraph;

根据书上的伪代码，写出三个要用到的方法

//返回顶点v在图G中的位置int LocateVex(ALGraph G, char v){for (int i = 0; i < G.vexnum; i++){if (v == G.vertices[i].data)return i;}return -1;}//返回v的第一个邻接顶点int FirstAdjVex(ALGraph G, int v){if (G.vertices[v].firstarc)return G.vertices[v].firstarc->adjvex;return -1;}//返回顶点v相对于邻接点w的下一个邻接点int NextAdjVex(ALGraph G, int v, int w){ArcNode *p;p = G.vertices[v].firstarc;if (p){while (p){if (w == p->adjvex){if (nullptr == p->nextarc)return -1;elsereturn p->nextarc->adjvex;}p = p->nextarc;}}return -1;}

下面是本体，一分钟改写出的构造图的方法！

//采用邻接表构造图Gvoid CreateGraph(ALGraph &G){int i, j, weight;char v, v1, v2;ArcNode *p, *q = nullptr;cout << "请输入图类型的序号：\n1.DG(有向图)\n2.DN(有向网\n3.UDG(无向图)\n4.UDN(无向网)" << endl;cin >> G.kind;cout << "请输入图G的顶点数和弧（边）数：";cin >> G.vexnum >> G.arcnum;//构造邻接表for (i = 0; i < G.vexnum; i++){cout << "请输入顶点vex[" << i << "]的值：";cin >> G.vertices[i].data;G.vertices[i].firstarc = nullptr;}cout << endl;for (j = 0; j < G.arcnum; j++){cout << "请输入第" << j << "条弧（边）的两个端点：";cin >> v1 >> v2;q = G.vertices[LocateVex(G, v1)].firstarc;p = new ArcNode;p->adjvex = LocateVex(G, v2);p->nextarc = nullptr;if (1 == G.kind || 3 == G.kind)p->weight = 1;else{cout << "请输入该弧（边）的权值：";cin >> weight;p->weight = weight;}if (q){while (q->nextarc)q = q->nextarc;q->nextarc = p;}elseG.vertices[LocateVex(G, v1)].firstarc = p;if (3 == G.kind || 4 == G.kind){q = G.vertices[LocateVex(G, v2)].firstarc;p = new ArcNode;p->adjvex = LocateVex(G, v1);p->nextarc = nullptr;if (1 == G.kind || 3 == G.kind)p->weight = 1;else{p->weight = weight;}if (q){while (q->nextarc)q = q->nextarc;q->nextarc = p;}elseG.vertices[LocateVex(G, v2)].firstarc = p;}}}

根据书上的伪代码，写出深度优先遍历的递归方法

//深度优先遍历（递归）void DFS(ALGraph G, int v){visited[v] = true;cout << G.vertices[v].data << " ";for (int i = FirstAdjVex(G, v); i >= 0; i = NextAdjVex(G, v, i)){if (!visited[i])DFS(G, i);}}void DFSTraverse(ALGraph G){int i;cout << "深度优先结果：" << endl;for (i = 0; i < G.vexnum; i++)visited[i] = false;for (i = 0; i < G.vexnum; i++){if (!visited[i])DFS(G, i);}cout << endl;}

打印函数在测试的时候不可少

//打印邻接表void PrintALGraph(ALGraph G){ArcNode *p;for (int i = 0; i < G.vexnum; i++){cout << G.vertices[i].data;if (G.vertices[i].firstarc){p = G.vertices[i].firstarc;while (p){if (3 == G.kind || 4 == G.kind)cout << " - " << G.vertices[p->adjvex].data;elsecout << "→" << G.vertices[p->adjvex].data;p = p->nextarc;}}cout << endl;}}

最后配上主函数

int main(){ALGraph graph;CreateGraph(graph);PrintALGraph(graph);DFSTraverse(graph);system("pause");return 0;}