ó úŁŐ\c@s§dZdjdgƒZddddddd gZd d lZd d lmZd d „Z d d„Z d d„Z d d„Z d d„Z d d„Zd d„Zd S(sş ================== Depth-first search ================== Basic algorithms for depth-first searching. Based on http://www.ics.uci.edu/~eppstein/PADS/DFS.py by D. Eppstein, July 2004. s sAric Hagberg t dfs_edgestdfs_treetdfs_predecessorstdfs_successorstdfs_preorder_nodestdfs_postorder_nodestdfs_labeled_edgesi˙˙˙˙N(t defaultdictc cs|dkr|}n |g}tƒ}xŐ|D]Í}||krFq.n|j|ƒ|t||ƒfg}xŒ|rú|d\}}yTt|ƒ}||krŘ||fV|j|ƒ|j|t||ƒfƒnWqotk rö|jƒqoXqoWq.WdS(s9Produce edges in a depth-first-search starting at source.i˙˙˙˙N(tNonetsettaddtitertnexttappendt StopIterationtpop( tGtsourcetnodestvisitedtstarttstacktparenttchildrentchild((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pyRs&            $ cCstjt|d|ƒƒS(s7Return directed tree of depth-first-search from source.R(tnxtDiGraphR(RR((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pyR1scCs td„t|d|ƒDƒƒS(sDReturn dictionary of predecessors in depth-first-search from source.css!|]\}}||fVqdS(N((t.0tstt((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pys 8sR(tdictR(RR((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pyR6scCsJttƒ}x1t|d|ƒD]\}}||j|ƒqWt|ƒS(sBReturn dictionary of successors in depth-first-search from source.R(RtlistRR R(RRtdRR((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pyR;s cCs#d„tj|d|ƒDƒ}|S(sSProduce nodes in a depth-first-search post-ordering starting from source. css.|]$\}}}|ddkr|VqdS(tdirtreverseN((RtutvR ((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pys Gs R(RR(RRtpost((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pyRCscCs#d„tj|d|ƒDƒ}|S(sFProduce nodes in a depth-first-search pre-ordering starting at source.css.|]$\}}}|ddkr|VqdS(R!tforwardN((RR#R$R ((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pys Ps R(RR(RRtpre((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pyRNsc csr|dkr|}n |g}tƒ}xD|D]<}||krFq.n||idd6fV|j|ƒ|t||ƒfg}xŃ|rT|d\}}yst|ƒ}||krÍ||idd6fVn?||idd6fV|j|ƒ|j|t||ƒfƒWq„tk rP|jƒ|rQ|dd|idd6fVqQq„Xq„W||idd6fVq.WdS(s|Produce edges in a depth-first-search starting at source and labeled by direction type (forward, reverse, nontree). R&R!i˙˙˙˙tnontreeiR"N(RR R R R R RR( RRRRRRRRR((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pyRWs0           !  ((t__doc__tjoint __author__t__all__tnetworkxRt collectionsRRRRRRRRR(((sh/Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/traversal/depth_first_search.pyt s