customSort.cpp

#include <iostream>
#include <unordered_map>
#include <algorithm>
using namespace std;

void customSort(int arr1[], int arr2[], int m, int n)
{

    unordered_map<int, int> freq;


    for (int i = 0; i < m; i++)
        freq[arr1[i]]++;


    int index = 0;


    for (int i = 0; i < n; i++)
    {

        while (freq[arr2[i]])
        {
            arr1[index++] = arr2[i];
            freq[arr2[i]]--;
        }

        freq.erase(arr2[i]);
    }


    int i = index;
    for (auto it = freq.begin(); it != freq.end(); ++it)
        while (it->second--)
            arr1[index++] = (it->first);
        
    sort(arr1 + i, arr1 + index);
}

int main()
{
    int arr1[] = { 5, 8, 9, 3, 5, 7, 1, 3, 4, 9, 3, 5, 1, 8, 4 };
    int arr2[] = { 3, 5, 7, 2 };

    int m = sizeof(arr1) / sizeof(arr1[0]);
    int n = sizeof(arr2) / sizeof(arr2[0]);

    customSort(arr1, arr2, m, n);

    cout << "After sorting the array is : ";
    for (int i = 0; i < m; i++)
        cout << arr1[i] << " ";
    cout << endl;

    return 0;
}