Rotate Array|Coding Problems

Problem Statement:

Given an unsorted array arr[] of size N, rotate it by D elements (clockwise).

Input:
The first line of the input contains T denoting the number of testcases. First line of each test case contains two space separated elements, N denoting the size of the array and an integer D denoting the number size of the rotation. Subsequent line will be the N space separated array elements.

Output:
For each testcase, in a new line, output the rotated array.

Constraints:
1 <= T <= 200
1 <= N <= 107
1 <= D <= N
0 <= arr[i] <= 105

Example:
Input:
2
5 2
1 2 3 4 5
10 3
2 4 6 8 10 12 14 16 18 20

Output:
3 4 5 1 2
8 10 12 14 16 18 20 2 4 6

Explanation :
Testcase 1: 1 2 3 4 5 when rotated by 2 elements, it becomes 3 4 5 1 2.

Code & Algorithm:

/* author : @akash */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define pb push_back
#define mod 1000000007
#define ld long double
void solve()
{
  int n,d;
  cin>>n>>d;
  int a[n];
  for(int i=0;i<n;++i)
  {
   cin>>a[i];
  }
  for(int i=0;i<d;++i)
  {
   int tmp=a[0];
   for(int j=1;j<n;++j)
   {
    a[j-1]=a[j];
   }
   a[n-1]=tmp;
  }
  for(int i=0;i<n;++i)
  {
   cout<<a[i]<<" ";
  }
}
int main()
{
 ios_base::sync_with_stdio(0);
 cin.tie(0);
 cout.tie(0);
 int t;
 cin>>t;
 while(t--)
 {
            solve();
            cout<<"\n";     
 }
 return 0;
}
// time complexity of this algorithm is : T(n)=O(n*d)

Thank You.

Akash Kumar

Software Engineer