189. Rotate Array (Medium)

Given an integer array nums, rotate the array to the right by k steps, where k is non-negative.

Example 1:

Input: nums = [1,2,3,4,5,6,7], k = 3
Output: [5,6,7,1,2,3,4]
Explanation:
rotate 1 steps to the right: [7,1,2,3,4,5,6]
rotate 2 steps to the right: [6,7,1,2,3,4,5]
rotate 3 steps to the right: [5,6,7,1,2,3,4]

Example 2:

Input: nums = [-1,-100,3,99], k = 2
Output: [3,99,-1,-100]
Explanation: 
rotate 1 steps to the right: [99,-1,-100,3]
rotate 2 steps to the right: [3,99,-1,-100]

Solutions 1 :

class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        vector<int> t(nums.size(),0);
        for(int i=0; i<nums.size(); i++)
            t[(k+i)%nums.size()] = nums[i];
        nums=t;
    }
};

Solutions 2 :

class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        int n = nums.size();
        k = k % n;
        reverse(nums.begin(), nums.end());
        reverse(nums.begin(), nums.begin()+k);
        reverse(nums.begin()+k, nums.end());
    }
};

Solution 3:

class Solution {
public:
    void reverse(vector<int>& nums, int left, int right) {
        int i=left;
        int j=right;

        while(i < j) {
            int temp = nums[i];
            nums[i] = nums[j];
            nums[j] = temp;
            i++;
            j--;
        }
    }

    void rotate(vector<int>& nums, int k) {
        k=k%nums.size();
        reverse(nums, 0, nums.size()-k-1);
        reverse(nums, nums.size()-k, nums.size()-1);
        reverse(nums, 0, nums.size()-1);
    }
};