[Two pointers-facing double pointers] Lintcode 39. Restore rotating sorted array

Lintcode 39. Restore rotated sorted array

Title description: Given a rotating sorted array, restore its sorting in place. (Ascending order) This

question is not well understood, and it needs to be implemented in depth later.

class Solution {
    
    
public:
    /**
     * @param nums: An integer array
     * @return: nothing
     */
    void recoverRotatedSortedArray(vector<int> &nums) {
    
    
        int offset = 0;
        for (int i = 1; i < nums.size(); ++i) {
    
    //寻找偏移量
            if (nums[i-1] > nums[i]) {
    
    
                offset = i;   
            }
        }
        if (0 == offset) {
    
    
            return;
        }
        offset = nums.size() - offset;
        
        int gcd = getGCD(offset, nums.size());
        for (int i = 0; i < gcd; ++i) {
    
    
            int next = (i + offset) % nums.size();
            //将每个数放到它们应该放的位置
            while (next != i) {
    
    
                int tmp = nums[i];
                nums[i] = nums[next];
                nums[next] = tmp;
                next = (next + offset) % nums.size();
            }
        }
    }
    
    //辗转相除法求最大公约数
    int getGCD(int a, int b) {
    
    
        if (0 == a % b) {
    
    
            return b;
        }
        return getGCD(b, a % b);
    }
};