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combineDuplicates

Language/Type: C++ linked lists pointers
Author: Marty Stepp (on 2016/06/16)

Write a member function named combineDuplicates that could be added to the LinkedIntList class. The function modifies the list by merging any consecutive neighboring nodes that contain the same element value into a single node whose value is the sum of the merged neighbors. For example, suppose a LinkedIntList variable named list stores the following values. The diagram shows the result of a call of list.combineDuplicates(); on the list. The underlined areas represent the neighboring duplicate elements that are merged in the final result.

{3, 3, 2, 4, 4, 4, -1, -1, 4, 12, 12, 12, 12, 48, -5, -5}       list

{3, 3, 2, 4, 4, 4, -1, -1, 4, 12, 12, 12, 12, 48, -5, -5}       list.combineDuplicates();

{6, 2, 12, -2, 4, 48, 48, -10}                                  result

If the list is empty or contains no duplicates, it should be unchanged by a call to your function.

Constraints: It is okay to modify the data field of existing nodes, if you like. Do not call any methods of the LinkedIntList class. You may, of course, refer to the private member variables inside the LinkedIntList. Note that the list does not have a size or mysize field. Do not construct any new ListNode objects in solving this problem (though you may create as many ListNode* pointer variables as you like). Do not use any auxiliary data structures to solve this problem (no array, vector, stack, queue, string, etc). Your code must run in no worse than O(N) time, where N is the length of the list. Your code must solve the problem by making only a single traversal over the list, not multiple passes.

Write the member function as it would appear in LinkedIntList.cpp. You do not need to declare the function header that would appear in LinkedIntList.h. Assume that you are adding this method to the LinkedIntList class as defined below:

class LinkedIntList {
private:
    ListNode* front;   // NULL for an empty list
    ...
    
public: 
    your code goes here;
};
Type your C++ solution code here:


This is a member function problem. Submit a member function that will become part of an existing C++ class. You do not need to write the complete class, just the member function described in the problem.

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