# Algorithm finding path with maximal ratio of white vertices [closed]

Recently I encountered an interesting graph problem and couldn't find proper solution: given undirected graph G = <V, E>, each vertex is either white or black. You need to find the path between given vertices s and t such that if W is the number of white vertices on that path and L is the length of the path, W/L is maximal possible. Obviously, the faster the algorithm is, the better.