c++ - Should I use mutable priority queue for dikjstra/A* algorithm? -


i trying implement a* algorithm , dikjstra algorithm special case of a* (just pass h(x){return 0;} a*), when choosing priority_queue, have 2 choices

  1. use empty priority_queue, , push start point when initializing, , "pop u, push neighbors of u satisfying conditions", in way, 1 node might pushed twice if common neighbor of 2 other nodes.
  2. use mutable priority queue supports update()/decreasekey()/increasekey(), choose data structures in boost::heap or (actually have) implement priority_queue myself, in way, nodes needed pushed container when initializing , handles them need kept.

what pros , cons of these 2 strategies , 1 more practical?

a common implementation of priority queue dijkstra's in c++ uses std::set, smallest item set.begin(), , can find exact item , erase it. can define facade allows access std::set priority queue-like interface , support additional update/erase/increasekey/decreasekey methods.

look here code samples dijkstra's implementations both std::set , std::priority_queue: https://www.topcoder.com/community/data-science/data-science-tutorials/power-up-c-with-the-standard-template-library-part-2/#dijkstra2

this article makes claim, performance naturally same, whether use std::priority_queue , discard stale items you've popped, or use std::set , erase old item immediately.


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