Challenge: Trace the Complete Path of a Journey

Problem Statement

In this problem, you have to implement the tracePath() function to find the starting point of a journey and print out the complete path from start to end. An illustration is also provided for your understanding.

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Function Prototype:

String tracePath(HashMap<String,String> map);

Here, map is a HashMap containing strings as keys and values corresponding to the cities, where the key is the departure city and the value is the arrival city

Output:

It returns the String containing the complete path from the start until the end of the journey.

Sample Input

map = 
{
    "NewYork" -> "Chicago"
    "Boston" -> "Texas"
    "Missouri" -> "NewYork"
    "Texas" -> "Missouri"
}
    key -> value

Sample Output

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

Explanation

The starting point of the path is “Boston”, so we find it first to help us traverse the whole path; we get to Texas through Boston, to Missouri through Texas, and so on.