leetcode-189. 旋转数组

输入: nums = [1,2,3,4,5,6,7], k = 3
输出: [5,6,7,1,2,3,4]
解释:
向右旋转 1 步: [7,1,2,3,4,5,6]
向右旋转 2 步: [6,7,1,2,3,4,5]
向右旋转 3 步: [5,6,7,1,2,3,4]

class Solution { 
   
public:
    void rotate(vector<int>& nums, int k) { 
   
        k %= nums.size();
        reverse(nums,0,nums.size() - 1);
        reverse(nums,0,k-1);
        reverse(nums,k,nums.size()-1);
    }
    void reverse(vector<int>&a,int l,int r){ 
   
        if(l>= r)return;
        for(int i = 0;i <= (r - l) / 2;i ++){ 
   
            int t = a[l + i];
            a[l + i] = a[r - i];
            a[r - i] = t;
        }
    }
};

class Solution { 
   
public:
    void rotate(vector<int>& nums,int k) { 
   
        k %= nums.size();
        int g = gca(nums.size(),k);
        for(int i = 0;i < g;i ++){ 
   
            int t = nums[i];
            int current = i;
            do{ 
   
                int next = (current + k) % nums.size();
                int a  = nums[next];
                nums[next] = t;
                current = next;
                t = a;
            }while(current != i);
        }
    }
    int lca(int a,int b){ 
   
        return a * b / lca(a,b);
    }
    int gca(int a,int b){ 
   
        return b == 0 ? a : gca(b, a % b);
    }
};