Rotate Array

c++

class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        if (nums.empty())
            return;
        k = k % nums.size();
        if (k == 0)
            return;

        k = nums.size() - k;
        for (int i = 0; i < k; ++i) {
            nums.push_back(nums[0]);
            nums.erase(nums.begin());
        }
    }
};

class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        if (nums.empty())
            return;
        k = k % nums.size();
        if (k == 0)
            return;

        reverse(nums.begin(), nums.end());
        reverse(nums.begin(), nums.begin() + k);
        reverse(nums.begin()+k, nums.end());
    }
};

python

class Solution(object):
    def rotate(self, nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: void Do not return anything, modify nums in-place instead.
        """
        if not nums:
            return

        k = k%len(nums)

        if k==0:
            return

        nums[0:len(nums)] = nums[0:len(nums)][::-1]#or nums.reverse()
        # nums = nums[::-1] didn't pass the online judge
        nums[0:k] = nums[0:k][::-1]
        nums[k:] = nums[k:][::-1]

reference:
https://leetcode.com/discuss/98234/three-times-reverse-c