1.1 --- a/lemon/bellman_ford.h	Sat Sep 26 07:21:54 2009 +0200
     1.2 +++ b/lemon/bellman_ford.h	Mon Sep 28 15:53:20 2009 +0200
     1.3 @@ -23,6 +23,7 @@
     1.4  /// \file
     1.5  /// \brief Bellman-Ford algorithm.
     1.6  
     1.7 +#include <lemon/list_graph.h>
     1.8  #include <lemon/bits/path_dump.h>
     1.9  #include <lemon/core.h>
    1.10  #include <lemon/error.h>
    1.11 @@ -775,7 +776,7 @@
    1.12      /// This function gives back a directed cycle with negative total
    1.13      /// length if the algorithm has already found one.
    1.14      /// Otherwise it gives back an empty path.
    1.15 -    lemon::Path<Digraph> negativeCycle() {
    1.16 +    lemon::Path<Digraph> negativeCycle() const {
    1.17        typename Digraph::template NodeMap<int> state(*_gr, -1);
    1.18        lemon::Path<Digraph> cycle;
    1.19        for (int i = 0; i < int(_process.size()); ++i) {