Version 5.0 The LEDA User Manual

With this iterator you can easily iterate through a graph in breadth first fashion :
graph G;
BFS_It it(G);
while (it.valid()) {
// do something reasonable with ’it.get_node()’
++it;
}
5. Implementation
Each operation requires constant time. Therefore, a normal breadth-first search needs
O(m + n) time.
13.18 Depth First Search (flexible) ( GIT DFS )
1. Definition
An instance algorithm of class GIT DFS< OutAdjIt, Stacktype, Mark > is an implementation
of an algorithm that traverses a graph in a depth first order. The stack used for
the search must be provided by the caller and contains the source(s) of the search.
• If the stack is only modified by pushing the iterator representing the source node
onto the stack, a normal depth first search beginning at the node of the graph is
performed.
• It is possible to initialize the stack with several iterators that represent different
roots of depth first trees.
• By modifying the stack while running the algorithm the behaviour of the algorithm
can be changed.
• After the algorithm performed a depth first search, one may push another iterator
onto the stack to restart the algorithm.
A next step may return a state which describes the last action. There are the following
three possibilities:
1. dfs shrink: an adjacency iterator was popped from the stack, i.e. the treewalk
returns in root-direction
2. dfs leaf: same as dfs shrink, but a leaf occured