Google Interview Question(Reverse an array in groups of given size)

Question:

Reverse an array in groups of a given size

Explanation:

We need to reverse an array with given group values.

For Example:

                    Array [1, 2, 3, 4, 5, 6, 7, 8,9,10,11]

                    Group value =4

                    Result=4 3 2 1 8 7 6 5 11 10 9 

Program:

#include <iostream> 
using namespace std; 
void rev(int arr[], int n, int group_val) 
{ 
    for (int i = 0; i < n; i += group_val) 
    { 
        int left = i; 
        int right = min(i + group_val - 1, n - 1); 
        while (left < right) 
            swap(arr[left++], arr[right--]); 
    } 
} 
int main() 
{ 
    int arr[] = {1, 2, 3, 4, 5, 6, 7, 8}; 
    int group_val = 3; 
    int n = sizeof(arr) / sizeof(arr[0]); 
    rev(arr, n, group_val); 
    for (int i = 0; i < n; i++) 
        cout << arr[i] << " ";
    return 0; 
} 

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