53 排序数组中查找数字

class Solution():
    def numcount(self,A,k):
        if A == [] or k not in A:
            return 0
        left = 0
        right = len(A)-1
        return self.getlastindex(A,k,left,right) - self.getfirstindex(A,k,left,right)+1


    def getfirstindex(self,A,k,left,right):
        mid = int((left+right)/2)
        if A[mid] == k:
            if mid == 0:
                return mid
            if A[mid-1] == k:
                return self.getfirstindex(A,k,left,mid-1)
            else:
                return mid

        elif A[mid] < k:
            return self.getfirstindex(A,k,mid+1,right)
        elif A[mid] > k:
            return self.getfirstindex(A,k,left,mid-1)

    def getlastindex(self,A,k,left,right):
        mid = int((left+right)/2)
        if A[mid] == k:
            if mid == right:
                return mid
            if A[mid+1] == k:
                return self.getlastindex(A,k,mid+1,right)
            else:
                return mid

        elif A[mid] < k:
            return self.getlastindex(A,k,mid+1,right)
        elif A[mid] > k:
            return self.getlastindex(A,k,left,mid-1)




s = Solution()
A = [1,2,3,3,3,4,5]
print(s.numcount(A,3))