Consider an oriented graph (multi-graph). Assume some set of vertexes is marked 'Init1','Init2','Init3'... and another set of vertexes is marked by 'Final1','Final2',... I am interested in the "efficient" algorithms which will determine is it possible to "MOVE" markers "InitNN" to positions 'FinalNN'. Where we allowed to "MOVE" marker from a vertex to an outgoing edge and from incoming edge to corresponding vertex. With the CONSTRAINT that two markers are NOT allowed to be at the same place. **Question** There can be many approaches to solve the problem, I am interested in analysis their complexity. Any ideas are welcome. For example if graph is "random" in certain sense what can be the algorithm the least average complexity ? Where complexity is counted in number of operations (write a C-code, compile to and calculate the number of cycles - this is well-defined complexity measure, different compilers and CPU will give approximately same result). **Example of algorithm** It seems the simplest way to solve a problem is the following. Essentially it can be reduced to determining where two vertexes are connected in some bigger graph, which in turn can be solved by "wave algorithm". I mean let us enumerate all possible marker configurations - it will give vertexes of the "new graph". Let us connect two vertexes(configurations) if there is a "MOVE" which goes form one to another. By "wave algorithm" (it is Russian name I am not sure in English translation) I mean the following - take an initial vertex and find all connected to it; next step find all vertexes connected to vertexes found on the previous step; and so on.... **Question** What about efficiency of this algorithm ? Can one propose better ?