掃描一遍建立哈希表贴汪，第二遍判斷哈希值悄晃。代碼如下：
class Solution(object):
def containsDuplicate(self, nums):
"""
:type nums: List[int]
:rtype: bool
"""
if len(nums) == 0 or len(nums) == 1:
return False
dic = {}
for n in nums:
if n not in dic:
dic[n] = 1
else:
dic[n] += 1
for n in nums:
if dic[n] > 1:
return True
return False
