Search in Rotated Sorted Array.cpp

class Solution
{
public:
    int search(vector<int> &nums, int target)
    {
        int l = 0, r = nums.size() - 1;
        while (l <= r)
        {
            int mid = (l + r) / 2;
            if (target == nums[mid])
                return mid;
            // there exists rotation; the middle element is in the left part of the array
            if (nums[mid] > nums[r])
            {
                if (target < nums[mid] && target >= nums[l])
                    r = mid - 1;
                else
                    l = mid + 1;
            }
            // there exists rotation; the middle element is in the right part of the array
            else if (nums[mid] < nums[l])
            {
                if (target > nums[mid] && target <= nums[r])
                    l = mid + 1;
                else
                    r = mid - 1;
            }
            // there is no rotation; just like normal binary search
            else
            {
                if (target < nums[mid])
                    r = mid - 1;
                else
                    l = mid + 1;
            }
        }
        return -1;
    }
}