# 1436. Destination City """ given the array 'paths' where 'paths[i] = [citya[i], cityb[i]]' means there exists a direct path going from 'citya[i]' to 'cityb[i]'. return the destination city that is the city without any path outgoing to another city. it is guaranteed that the graph of paths forms a line without any loop, therefore there will be exactly one destination. """ class Solution(object): def destCity(self, paths): """ :type paths: List[List[str]] :rtype: str """ cities = set() for i in paths: cities.add(i[0]) for i in paths: dest = i[1] if dest not in cities: return dest return "" if __name__ == "__main__": obj = Solution() print( obj.destCity( paths=[["London", "New York"], ["New York", "Lima"], ["Lima", "Sao Paulo"]] ) ) print(obj.destCity(paths=[["B", "C"], ["D", "B"], ["C", "A"]]))