Data Structure Array: Program for array rotation

http://www.geeksforgeeks.org/array-rotation/

O(n), O(1)

 #include <iostream>
 #include <vector>
 #include <algorithm>
 #include <queue>
 #include <stack>
 #include <string>
 #include <fstream>
 #include <map>
 using namespace std;

 int gcd(int a, int b) {
     return b == ? a : gcd(b, a % b);
 }

 void leftrotate(int arr[], int d, int n) {
     for (int i = ; i < gcd(d, n); i++) {
         int tmp = arr[i];
         int j = i;
         while () {
             int k = j + d;
             if (k >= n) k -= n;
             if (k == i) break;
             arr[j] = arr[k];
             j = k;
         }
         arr[j] = tmp;
     }
 }

 int main() {
     int arr[] = {, , , , , , };
     leftrotate(arr, , );
     for (int i = ; i < ; i++) cout << arr[i] << " ";
     return ;
 }

O(n), O(1)

 #include <iostream>
 #include <vector>
 #include <algorithm>
 #include <queue>
 #include <stack>
 #include <string>
 #include <fstream>
 #include <map>
 using namespace std;

 void reverse(int arr[], int a, int b) {
     for (int i = ; i < (b-a)/; i++) swap(arr[a+i], arr[b--i]);
 }

 void leftrotate(int arr[], int d, int n) {
     reverse(arr, , d);
     reverse(arr, d, n);
     reverse(arr, , n);
 }

 int main() {
     int arr[] = {, , , , , , };
     leftrotate(arr, , );
     for (int i = ; i < ; i++) cout << arr[i] << " ";
     return ;
 }