/* dfs-demo.c Driver program demonstrating DFS numbering and edge labeling. */ /* Copyright 2003-2020 by Steven S. Skiena; all rights reserved. Permission is granted for use in non-commerical applications provided this copyright notice remains intact and unchanged. These programs appear in my books: "The Algorithm Design Manual" by Steven Skiena, second edition, Springer, London 2008. See out website www.algorist.com for additional information or https://www.amazon.com/exec/obidos/ASIN/1848000693/thealgorith01-20 "Programming Challenges: The Programming Contest Training Manual" by Steven Skiena and Miguel Revilla, Springer-Verlag, New York 2003. See our website www.programming-challenges.com for additional information, or http://www.amazon.com/exec/obidos/ASIN/0387001638/thealgorithmrepo/ */ #include #include #include "bfs-dfs.h" #include "queue.h" extern bool processed[]; /* which vertices have been processed */ extern bool discovered[]; /* which vertices have been found */ extern int parent[]; /* discovery relation */ int entry_time[MAXV+1]; /* time of vertex entry */ int exit_time[MAXV+1]; /* time of vertex exit */ int time; /* current event time */ void process_vertex_early(int v) { time = time + 1; entry_time[v] = time; printf("entered vertex %d at time %d\n",v, entry_time[v]); } void process_vertex_late(int v) { time = time + 1; exit_time[v] = time; printf("exit vertex %d at time %d\n",v, exit_time[v]); } void process_edge(int x, int y) { int class; /* edge class */ class = edge_classification(x, y); if (class == BACK) { printf("back edge (%d,%d)\n", x, y); } else if (class == TREE) { printf("tree edge (%d,%d)\n", x, y); } else if (class == FORWARD) { printf("forward edge (%d,%d)\n", x, y); } else if (class == CROSS) { printf("cross edge (%d,%d)\n", x, y); } else { printf("edge (%d,%d)\n not in valid class=%d", x, y, class); } } int main(void) { graph g; int i; read_graph(&g, false); print_graph(&g); initialize_search(&g); dfs(&g, 1); for (i = 1; i <= g.nvertices; i++) { find_path(1, i, parent); } printf("\n"); return 0; }