LeetCode之“数组”：Rotate Array

　　题目链接

　　题目要求：

　　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.

　　Hint:
　　Could you do it in-place with O(1) extra space?

　　Related problem: Reverse Words in a String II

　　Credits:
　　Special thanks to @Freezen for adding this problem and creating all test cases.

　　这道题要注意的是：k可能比数组的大小还大。程序如下：

 class Solution {
 public:
     void permute(vector<int>& nums, int start, int end)
     {
         if(start > end)
             return;

         int sz = (end - start) /  + ;
         for(int i = ; i < sz; i++)
         {
             int tmp = nums[start+i];
             nums[start+i] = nums[end-i];
             nums[end-i] = tmp;
         }
     }

     void rotate(vector<int>& nums, int k) {
         int sz = nums.size();
         if(sz <= k)
             k -= sz;
         if(k == )
             return;
         permute(nums, , sz - k - );
         permute(nums, sz - k, sz - );
         permute(nums, , sz - );
     }
 };