LeetCode 1: single-number

Given an array of integers, every element appears twice except for one. Find that single one.

solution:

class solution:

def singleNumber(self,A):

　　A.sort()
　　for i in range(1,len(A)):
　　　　if i%2=1 && A[i]!=A[i-1]:
　　　　return A[i-1]

if __name__ == '__main__':
print Solution().singleNumber([1, 1, 2, 2, 3])