153_Find Minimum in Rotated Sorted Array

class Solution {
public:
    int findMin(vector<int>& A) {
        int n = A.size()-1;
        long mid, left = 0, right = A.size()-1;
        if(A[0] <= A[n])
            return A[0];
        while( left <= right)
        {
            mid = (left + right) /2;
            //cout<<left<<" "<<mid<<" "<<right<<" \n";
            if( mid < right && A[mid] > A[mid +1 ])
                return A[mid+1];
            if( (A[mid] <= A[ (mid +n -1) % n ]) && (A[mid] <= A[ ( mid +1) % n ]) )
                return A[mid];
            else if( A[mid] >= A[left] )
                left = mid+1;
            else
                right = mid-1;
        }
        return -1;
    }
};