DFS(邻接表表示)
#define _CRT_SECURE_NO_WARNINGS #include <iostream> using namespace std; #define PATH #define VERTEX_NUM 8 #ifdef PATH int count = 1; #endif bool visited[VERTEX_NUM + 1]; // 访问标志数组(备忘表) struct ArcNode { int adjvex; ArcNode *nextarc; }; int FirstAdjVex(ArcNode *G[VERTEX_NUM + 1], int v) { if (G[v] == NULL) // v是孤立顶点 return -1; return G[v]->adjvex; } int NextAdjVex(ArcNode *G[VERTEX_NUM + 1], int v, int w) { for (ArcNode *p = G[v]; p != NULL; p = p->nextarc) { if (p->adjvex == w) { // 找到w,将返回 if (p->nextarc == NULL) // w已是v的最后一个邻接点 return -1; return p->nextarc->adjvex; } } cout << "错误!没找到w" << endl; return -1; } void DFS(ArcNode *G[VERTEX_NUM + 1], int v) { // 从第v个顶点出发递归地深度优先遍历图G。 int w; visited[v] = true; cout << v << endl; for (w = FirstAdjVex(G, v); w != -1; w = NextAdjVex(G, v, w)) { #ifdef PATH cout << "------------------" << count++ << "----" << v << "->" << w << endl; // 1 #endif if (!visited[w]) { // 对v的尚未访问的邻接顶点w递归调用DFS DFS(G, w); #ifdef PATH cout << v << endl; // 有待研究? // 2 #endif } } #ifdef PATH cout << "回溯路径" << v << "->"; // 3 #endif } void DFSTraverse(ArcNode *G[VERTEX_NUM + 1]) { // 对图G作深度优先遍历。 int v; for (v = 1; v <= VERTEX_NUM; ++v) visited[v] = false; // 访问标志数组初始化 for (v = 1; v <= VERTEX_NUM; ++v) { // 若是连通图,则v=1即全遍历到 if (!visited[v]) DFS(G, v); // 对尚未访问的顶点调用DFS } cout << endl; } void CreatAdjListGraph(ArcNode *G[VERTEX_NUM + 1]) { int a; int b; while (cin >> a >> b, !(a == 0 && b == 0)) { //以0 0作为输入结束 ArcNode *p = new ArcNode; if (p == NULL) { cout << "OVERFLOW!" << endl; exit(OVERFLOW); } p->adjvex = b; p->nextarc = G[a]; // 头插入 G[a] = p; ArcNode *q = new ArcNode; if (q == NULL) { cout << "OVERFLOW!" << endl; exit(OVERFLOW); } q->adjvex = a; q->nextarc = G[b]; // 头插入 G[b] = q; } } void Display(ArcNode *G[VERTEX_NUM + 1]) { for (int i = 1; i <= VERTEX_NUM; i++) { // 输出邻接表 cout << i; for (ArcNode *p = G[i]; p != NULL; p = p->nextarc) { cout << "->" << p->adjvex ; } cout << endl; } } void Free(ArcNode *G[VERTEX_NUM + 1]) { for (int i = 1; i <= VERTEX_NUM; i++) { for (ArcNode *p = G[i]; p != NULL;) { ArcNode *q = p; p = p->nextarc; delete q; q = NULL; } } } int main(int argc, char **argv) { freopen("cin.txt", "r", stdin); ArcNode *G[VERTEX_NUM + 1] = {NULL}; CreatAdjListGraph(G); // 建图(邻接表表示) Display(G); // 显示图 DFSTraverse(G); // 遍历图 Free(G); // 释放图 return 0; } /* cin.txt: 1 2 2 4 2 5 8 4 8 5 1 3 3 6 3 7 6 7 0 0 */