deletion.cpp

#include <iostream>
using namespace std;

void merge(int arr[], int l, int mid, int r)
{
    int n1 = mid - l + 1;
    int n2 = r - mid;

    int a[n1];
    int b[n2];

    for (int i = 0; i < n1; i++)
    {
        a[i] = arr[l + i];
    }
    for (int i = 0; i < n2; i++)
    {
        b[i] = arr[mid + 1 + i];
    }

    int i = 0;
    int j = 0;
    int k = l;

    while (i < n1 && j < n2)
    {
        if (a[i] < b[j])
        {
            arr[k] = a[i];
            k++;
            i++;
        }
        else
        {
            arr[k] = b[j];
            k++;
            j++;
        }
    }
    while (i < n1)
    {
        arr[k] = a[i];
        k++;
        i++;
    }
    while (j < n2)
    {
        arr[k] = b[j];
        k++;
        j++;
    }
}

void mergeSort(int arr[], int l, int r)
{
    if (l < r)
    {
        int mid = (l + r) / 2;
        mergeSort(arr, l, mid);
        mergeSort(arr, mid + 1, r);

        merge(arr, l, mid, r);
    }
}

int deleteArr(int arr[], int n)
{
    mergeSort(arr, 0, n - 1);
    int dup = 0;
    for (int i = 0; i < n - 1; i++)
    {
        if (arr[i] == arr[i + 1])
        {
            dup = arr[i];
            
        }
    }
    int count = 0;
    for(int i=0; i<n; i++)
    {
        if(arr[i] == dup)
        {
            count++;
        }
    }

    return (n-count);
}


int main()
{

    int arr[] = {1,2,2,3};
    int n = sizeof(arr) / sizeof(arr[0]);
    int dup = 0;
    cout << deleteArr(arr, n);

    return 0;
}