LeetCode之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.

[show hint]

Related problem: Reverse Words in a String II

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

   

    

     

      

     
     

      

       class Solution {
      
     
    

     

      

     
     

      

       	public void rotate(int[] nums, int k) {
      
     
    

     

      

     
     

      

        if (nums == null || nums.length == 0 || k <= 0)
      
     
    

     

      

     
     

      

        return;
      
     
    

     

      

     
     

      

        int length = nums.length;
      
     
    

     

      

     
     

      

        int lastK = 0;
      
     
    

     

      

     
     

      

        if (k < length)
      
     
    

     

      

     
     

      

        lastK = k;
      
     
    

     

      

     
     

      

        else 
      
     
    

     

      

     
     

      

        lastK = k % length;
      
     
    

     

      

     
     

      

        if (lastK == 0)
      
     
    

     

      

     
     

      

        return;
      
     
    

     

      

     
     

      

        change(nums, length);
      
     
    

     

      

     
     

      

        change(nums, lastK);
      
     
    

     

      

     
     

      

        int i = lastK, j = length - 1;
      
     
    

     

      

     
     

      

        while (i < j) {
      
     
    

     

      

     
     

      

        int temp = nums[i];
      
     
    

     

      

     
     

      

        nums[i] = nums[j];
      
     
    

     

      

     
     

      

        nums[j] = temp;
      
     
    

     

      

     
     

      

        i++;
      
     
    

     

      

     
     

      

        j--;
      
     
    

     

      

     
     

      

        }
      
     
    

     

      

     
     

      

        
      
     
    

     

      

     
     

      

        }
      
     
    

     

      

     
     

      

        public void change(int[] nums, int length) {
      
     
    

     

      

     
     

      

        for (int i = 0; i < length / 2; ++i) {
      
     
    

     

      

     
     

      

        int temp = nums[i];
      
     
    

     

      

     
     

      

        nums[i] = nums[length - i - 1];
      
     
    

     

      

     
     

      

        nums[length - i - 1] = temp;
      
     
    

     

      

     
     

      

        }
      
     
    

     

      

     
     

      

        }
      
     
    

     

      

     
     

      

       }