rotate.cpp

class Solution {
private:
    void reverse(vector<int>& nums, int start, int end) {
        int tmp;
        
        while(start < end) {
            tmp = nums[start];
            nums[start] = nums[end];
            nums[end] = tmp;
            
            start++;
            end--;
        }
    }
public:
    void rotate(vector<int>& nums, int k) {
        int n = nums.size();
        k = k % n;
        
        reverse(nums, 0, n - 1);
        reverse(nums, 0, k - 1);
        reverse(nums, k, n - 1);
    }
};