Rotate Array

Rotate an array of n elements to the right by k steps.

For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].

Note:
Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.

Related problem: Reverse Words in a String II

Analyse: Flip the entire array, flip the first k elements, then flip the remaining elements.

Runtime: 16ms. Beat 98.91%...

 1 class Solution {
 2 public:
 3     void flipArray(vector<int>& nums, int start, int end){
 4         for(int i = start, j = end; i < j; i++, j--)
 5             swap(nums[i], nums[j]);
 6     }
 7     
 8     void rotate(vector<int>& nums, int k) {
 9         if(nums.empty()) return;
10         
11         k %= nums.size(); // if k is larger than nums.size()
12         if(k == 0) return;
13         
14         flipArray(nums, 0, nums.size() - 1);
15         flipArray(nums, 0, k - 1);
16         flipArray(nums, k, nums.size() - 1);
17     }
18 };