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# K friends want to meet in a city. Find the smallest amoutn of gas they need.

We have N cities and M both-way roads. K friends that live in a specified city want to get to another city(called Z). Every road costs 1 unit of gas. If 2 or more friends meet in a city they can continue the road using only 1 car(I guess someone abandons his car XD). The cars have an infinite space(meaning that there is an infinite number of friends that can travel in a single car). Print the minimum amount of gas they need to get to Z or minus 1 if one or more friends can't get there. I tried using the Dijkstra's algorithm to compute the amount of gas every single friend need to get from their city to Z. I calculated the sum of those results. After that I also stored the road they used to get to Z and then I looked at their roads and computed how many friends have passed through the same node, so that I could substract from the earlier sum (no. friends -1), meaning that only one car consumed gas there, not no friends cars. It seems to not work(it only gets 10/100 points). I was wondering if someone can help me, or tell me what is wrong with my idea. Have great day! :) P.S: there can be a maximum of 10 friends, and a maximum of 200 cities.