11.二分法：旋转数组的最小数字

class Solution():
    def findmin(self,A,left,right):
        if right - left == 1:
            return A[right]

        mid = int((left+right)/2)

        if A[left] <= A[right]:
            return A[left]

        if A[mid] >= A[left]:
            self.findmin(A,mid,right)

        if A[mid] <= A[right]:
            self.findmin(A,left,mid)

#test
s = Solution()
print(s.findmin([3,4,5,1,2],0,4))