public static void main(String args[]){
        int input[][] = {{0, 15, 80, 90},
                         {-1, 0,  40, 50},
                         {-1, -1,  0,  70},
                         {-1, -1,  -1,  0}};
        MinimumCostTrainTicket mctt = new MinimumCostTrainTicket();
        System.out.println(mctt.minCost(input));
    }
http://www.geeksforgeeks.org/find-the-minimum-cost-to-reach-a-destination-where-every-station-is-connected-in-one-direction/
src/com/interview/dynamic/MinimumCostTrainTicket.java