Challenge 4: Trace the Complete Path of a Journey

Problem statement

You have to implement the tracePath(Dictionary<string, string> map) function, which will take in an array of source-destination pairs and return the correct sequence of the whole journey from the first city to the last.

Input

This is a Dictionary of type <string, string> containing string pairs of source-destination cities.

Output

It is a string of source-destination pairs in the correct order.

Sample input

map = {
  "NewYork": "Chicago",
  "Boston": "Texas",
  "Missouri": "NewYork",
  "Texas": "Missouri"
}
key: value

Sample output

Boston->Texas, Texas->Missouri, Missouri->NewYork, NewYork->Chicago