Python implementation for LND path finding algorithm
These implementations use some form of the Dijkstra algorithm which is implemented in the open source networkx python lib https://networkx.github.io/documentation/stable/reference/algorithms/shortest_paths.html also electrum wallet is working on lightning. I think they followed pretty much the lnd code base so one could check their pathfing implementation at https://github.com/spesmilo/electrum/blob/master/electrum/lnrouter.py