private int getCost(Set<Integer> set, int prevVertex, Map<Index, Integer> minCostDP) {
        set.remove(prevVertex);
        Index index = Index.createIndex(prevVertex, set);
        int cost = minCostDP.get(index);
        set.add(prevVertex);
        return cost;
    }
Date 11/17/2015
@author Tushar Roy

Help Karp method of finding tour of traveling salesman.

Time complexity - O(2^n * n^2)
Space complexity - O(2^n)

https://en.wikipedia.org/wiki/Held%E2%80%93Karp_algorithm
src/com/interview/graph/TravelingSalesmanHeldKarp.java