Step by Step solution about How to resolve the algorithm Order by pair comparisons step by step in the C++ programming language

The provided C++ code demonstrates two approaches to sorting a list of strings interactively, using the input from the user to determine the order of the strings.

1. Binary Insertion Sort Using Binary Search:

• The first approach, implemented in the first InteractiveCompare function and main function, uses a binary insertion sort. This method starts with an empty sorted list and repeatedly inserts each item from the unsorted list into its proper position within the sorted list, while minimizing the number of comparisons required.

• The InteractiveCompare function is a comparison function used by the lower_bound algorithm, which performs a binary search. It prompts the user to input whether one string should come before another and returns true if it should come before, otherwise returns false.

• In the main function, the list of strings is iterated over, and each string is inserted into the sorted list using the lower_bound function, which uses the InteractiveCompare function to compare the new string with the existing strings in the sorted list.

• The final sorted list is printed using the PrintOrder function.

2. Using the Standard Library's Sort Function:

• The second approach, implemented in the second InteractiveCompare function and main function, uses the standard library's sort function with the InteractiveCompare function as the comparison function.

• The InteractiveCompare function is the same as in the previous approach, but it is used to directly compare elements during sorting.

• In the main function, the sort function is called, passing the InteractiveCompare function as an argument. This sorts the list of strings interactively based on user input.

• The final sorted list is printed using the PrintOrder function.

Both approaches provide interactive sorting mechanisms that solicit user input to determine the order of the strings in the list. The binary insertion sort approach can potentially reduce the number of comparisons required, but the standard library's sort function with the custom comparison function is simpler to implement.

#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

bool InteractiveCompare(const string& s1, const string& s2)
{
    if(s1 == s2) return false;  // don't ask to compare items that are the same
    static int count = 0;
    string response;
    cout << "(" << ++count << ") Is " << s1 << " < " << s2 << "? ";
    getline(cin, response);
    return !response.empty() && response.front() == 'y';
}

void PrintOrder(const vector<string>& items)
{
    cout << "{ ";
    for(auto& item : items) cout << item << " ";
    cout << "}\n";
}

int main()
{
    const vector<string> items
    {
        "violet", "red", "green", "indigo", "blue", "yellow", "orange"
    };
    
    vector<string> sortedItems;
    
    // Use a binary insertion sort to order the items.  It should ask for
    // close to the minimum number of questions required
    for(auto& item : items)
    {
        cout << "Inserting '" << item << "' into ";
        PrintOrder(sortedItems);
        // lower_bound performs the binary search using InteractiveCompare to
        // rank the items
        auto spotToInsert = lower_bound(sortedItems.begin(),
                                        sortedItems.end(), item, InteractiveCompare);
        sortedItems.insert(spotToInsert, item);
    }
    PrintOrder(sortedItems);
    return 0;
}


#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

bool InteractiveCompare(const string& s1, const string& s2)
{
    if(s1 == s2) return false;  // don't ask to compare items that are the same
    static int count = 0;
    string response;
    cout << "(" << ++count << ") Is " << s1 << " < " << s2 << "? ";
    getline(cin, response);
    return !response.empty() && response.front() == 'y';
}

void PrintOrder(const vector<string>& items)
{
    cout << "{ ";
    for(auto& item : items) cout << item << " ";
    cout << "}\n";
}

int main()
{
    vector<string> items
    {
        "violet", "red", "green", "indigo", "blue", "yellow", "orange"
    };
    
    sort(items.begin(), items.end(), InteractiveCompare);
    PrintOrder(items);
    return 0;
}