rotate.java

class Solution {
    public void rotate(int[] nums, int k) {
        k %= nums.length;
        reverse(nums, 0, nums.length-1);
        reverse(nums,0, k-1);
        reverse(nums, k, nums.length-1);        
    }
    
    public void reverse(int [] nums, int start, int end)
    {
        while(start <= end)
        {
            int temp = nums[start];
            nums[start] = nums[end];
            nums[end] = temp;
            start++;
            end--;
        }
    }
}