logo CodeStepByStep logo

rarest

Language/Type: C++ map collections STL
Related Links:

Write a function named rarest that accepts a reference to a map from strings to strings as a parameter and returns the value that occurs least frequently in the map. If there is a tie, return the value that comes earlier in ABC order. For example, if a variable called map containing the following elements:

{"Alyssa":"Harding", "Char":"Smith", "Dan":"Smith", "Jeff":"Jones", "Kasey":"Jones",
 "Kim":"Smith", "Morgan":"Jones", "Ryan":"Smith", "Stef":"Harding"}

Then a call of rarest(map) would return "Harding" because that value occurs 2 times, fewer than any other. Note that we are examining the values in the map, not the keys. If the map passed is empty, throw a string exception.

Constraints: Obey the following restrictions in your solution.

  • You may create one additional data structure (stack, queue, set, map, etc.) as auxiliary storage. (You can have as many simple variables as you like.)
  • You should not modify the contents of the map passed to your function.
    Declare your function in such a way that any caller can be sure that this will not happen.
  • Your solution should run in no worse than O(N log N) time, where N is the number of pairs in the map.
Function: Write a C++ function as described, not a complete program.

You must log in before you can solve this problem.

Log In

Need help?

Stuck on an exercise? Contact your TA or instructor.

If something seems wrong with our site, please

Is there a problem? Contact us.