title: Finding all paths in directed graph with specific cost
body: <p>Suppose we have the directed, weighted graph. Our task is to find all paths beetween two vertices (source and destination) which cost is less or equal =&lt; N. We visit every vertex only once. In later version I'd like to add a condition that the source can be the destination (we just make a loop).</p>
  
  <p>I think it can be done with modified Dijkstra's algorithm, but I have no idea how implement such thing. Thanks for any help.</p>