C++ Program To Remove Duplicates From Sorted Array

// Simple C++ program to remove duplicates
#include <iostream>
using namespace std;

// Function to remove duplicate 
// elements This function returns 
// new size of modified array.
int removeDuplicates(int arr[], int n)
{
    // Return, if array is empty or 
    // contains a single element
    if (n == 0 || n == 1)
        return n;

    int temp[n];

    // Start traversing elements
    int j = 0;

    // If current element is not equal 
    // to next element then store that 
    // current element
    for (int i = 0; i < n - 1; i++)
        if (arr[i] != arr[i + 1])
            temp[j++] = arr[i];

    // Store the last element as whether 
    // it is unique or repeated, it hasn't 
    // stored previously
    temp[j++] = arr[n - 1];

    // Modify original array
    for (int i = 0; i < j; i++)
        arr[i] = temp[i];

    return j;
}

// Driver code
int main()
{
    int arr[] = {1, 2, 2, 3, 4, 
                 4, 4, 5, 5};
    int n = sizeof(arr) / sizeof(arr[0]);

    // RemoveDuplicates() returns 
    // new size of array.
    n = removeDuplicates(arr, n);

    // Print updated array
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";

    return 0;
}

// This code is contributed by Aditya Kumar (adityakumar129)

// C++ program to remove 
// duplicates in-place
#include<iostream>
using namespace std;

// Function to remove duplicate 
// elements. This function returns 
// new size of modified array.
int removeDuplicates(int arr[], int n)
{
    if (n==0 || n==1)
        return n;

    // To store index of next 
    // unique element
    int j = 0;

    // Doing same as done in Method 1
    // Just maintaining another updated 
    // index i.e. j
    for (int i = 0; i < n - 1; i++)
        if (arr[i] != arr[i + 1])
            arr[j++] = arr[i];

    arr[j++] = arr[n - 1];

    return j;
}

// Driver code
int main()
{
    int arr[] = {1, 2, 2, 3, 4, 
                 4, 4, 5, 5};
    int n = sizeof(arr) / sizeof(arr[0]);

    // removeDuplicates() returns new 
    // size of array.
    n = removeDuplicates(arr, n);

    // Print updated array
    for (int i=0; i<n; i++)
        cout << arr[i] << " ";

    return 0;
}