无向图的 DFS 和 BFS实现 （以邻接表存储的图）
1 #include <iostream> 2 #include <queue> 3 4 using namespace std; 5 6 #define MaxVertexNum 10 7 typedef int Vertex; 8 typedef int WeightType; 9 typedef char DataType; 10 11 bool Visited[MaxVertexNum] = { false }; 12 13 //边的定义 14 typedef struct ENode 15 { 16 Vertex V1, V2; //有向边<V1,V2> 17 WeightType Weight; //权重 18 }*Edge; 19 20 //邻接点的定义 21 typedef struct AdjVNode 22 { 23 Vertex AdjV; //邻接点下标 24 WeightType Weight; //边权重 25 struct AdjVNode *Next; //指向下一个邻接点的指针 26 }*PtrToAdjVNode; 27 28 //顶点表头结点的定义 29 typedef struct VNode 30 { 31 /* DataType Data; //存顶点的数据，很多情况下，顶点无数据，此时Data可以不用出现 */ 32 struct AdjVNode *FirstEdge; //边表头指针 33 }AdjList[MaxVertexNum]; 34 35 //图结点的定义 36 typedef struct GNode 37 { 38 int Nv; //顶点数 39 int Ne; //边数 40 AdjList G; //邻接表表示的图 41 }*LGraph; 42 43 44 LGraph BuildGraph(int vertex_num, int edge_num) 45 { 46 LGraph Graph = (LGraph)malloc(sizeof(struct GNode)); 47 Graph->Nv = vertex_num; 48 Graph->Ne = edge_num; 49 for (int i = 0; i < Graph->Nv; ++i) 50 Graph->G[i].FirstEdge = NULL; //初始化所有表头指针为NULL 51 52 Edge E = (Edge)malloc(sizeof(struct ENode)); 53 for (int i = 0; i < Graph->Ne; ++i) 54 { 55 printf("请输入第%d条边的起点和终点：", i+1); 56 cin >> E->V1 >> E->V2; 57 E->Weight = 1; 58 59 60 //这种插入方法将会使下标大的在前，小的在后，所以遍历的时候下标大的会先遍历 61 //插入边<V1,V2> 62 PtrToAdjVNode NewNode1 = (PtrToAdjVNode)malloc(sizeof(struct AdjVNode)); 63 NewNode1->AdjV = E->V2; 64 NewNode1->Weight = E->Weight; 65 NewNode1->Next = Graph->G[E->V1].FirstEdge; 66 Graph->G[E->V1].FirstEdge = NewNode1; 67 68 //无向图，还要插入边<V2,V1> 69 PtrToAdjVNode NewNode2 = (PtrToAdjVNode)malloc(sizeof(struct AdjVNode)); 70 NewNode2->AdjV = E->V1; 71 NewNode2->Weight = E->Weight; 72 NewNode2->Next = Graph->G[E->V2].FirstEdge; 73 Graph->G[E->V2].FirstEdge = NewNode2; 74 } 75 76 return Graph; 77 } 78 79 void Visit(LGraph Graph, Vertex V) 80 { 81 cout << V << ' '; 82 } 83 84 void ClearVisited() 85 { 86 for (int i = 0; i < MaxVertexNum; ++i) 87 Visited[i] = false; 88 } 89 90 void DFS(LGraph Graph, Vertex V) 91 { 92 Visit(Graph, V); 93 Visited[V] = true; 94 95 for (PtrToAdjVNode p = Graph->G[V].FirstEdge; p != NULL; p = p->Next) 96 { 97 if (!Visited[p->AdjV]) 98 DFS(Graph, p->AdjV); 99 } 100 } 101 102 void BFS(LGraph Graph, Vertex V) 103 { 104 Visit(Graph, V); 105 Visited[V] = true; 106 queue<Vertex> Q; 107 Q.push(V); 108 109 while(!Q.empty()) 110 { 111 Vertex W = Q.front(); 112 Q.pop(); 113 for (PtrToAdjVNode p = Graph->G[W].FirstEdge; p != NULL; p = p->Next) 114 { 115 if (!Visited[p->AdjV]) 116 { 117 Visit(Graph, p->AdjV); 118 Visited[p->AdjV] = true; 119 Q.push(p->AdjV); 120 } 121 } 122 } 123 } 124 125 int main() 126 { 127 int nv, ne; 128 cout << "请输入图的顶点数与边数："; 129 cin >> nv >> ne; 130 LGraph Graph = BuildGraph(nv, ne); 131 cout << endl; 132 cout << "请输入遍历起点："; 133 Vertex V; 134 cin >> V; 135 cout << "DFS: "; 136 DFS(Graph, V); 137 ClearVisited(); 138 cout <<endl; 139 cout << "BFS: "; 140 BFS(Graph, V); 141 142 143 return 0; 144 }
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