C++ Program to Split the array and add the first part to the end | Set 2

Given an array and split it from a specified position, and move the first part of array add to the end. 

Examples:

Input : arr[] = {12, 10, 5, 6, 52, 36}
            k = 2
Output : arr[] = {5, 6, 52, 36, 12, 10}
Explanation : Split from index 2 and first 
part {12, 10} add to the end .

Input : arr[] = {3, 1, 2}
           k = 1
Output : arr[] = {1, 2, 3}
Explanation : Split from index 1 and first
part add to the end.

A O(n*k) solution is discussed here. 
This problem can be solved in O(n) time using the reversal algorithm discussed below, 
1. Reverse array from 0 to n – 1 (where n is size of the array). 
2. Reverse array from 0 to n – k – 1. 
3. Reverse array from n – k to n – 1.

C++

// C++ program to Split the array and
// add the first part to the end
#include <bits/stdc++.h>

using namespace std;

/* Function to reverse arr[] from index start to end*/
void rvereseArray(int arr[], int start, int end)
{
    while (start < end) {
        int temp = arr[start];
        arr[start] = arr[end];
        arr[end] = temp;
        start++;
        end--;
    }
}

// Function to print an array
void printArray(int arr[], int size)
{
    for (int i = 0; i < size; i++)
        cout << arr[i] << " ";
}

/* Function to left rotate arr[] of size n by k */
void splitArr(int arr[], int k, int n)
{
    rvereseArray(arr, 0, n - 1);
    rvereseArray(arr, 0, n - k - 1);
    rvereseArray(arr, n - k, n - 1);
}

/* Driver program to test above functions */
int main()
{
    int arr[] = { 12, 10, 5, 6, 52, 36 };
    int n = sizeof(arr) / sizeof(arr[0]);
    int k = 2;

    // Function calling
    splitArr(arr, k, n);
    printArray(arr, n);

    return 0;
}

Output:

5 6 52 36 12 10 

Please refer complete article on Split the array and add the first part to the end | Set 2 for more details!