Single Number Problem : leetCode: array

 

Source Problem: https://leetcode.com/problems/single-number

This Solution Does not uses constant Space.

Solution:

class Solution(object):

    def singleNumber(self, nums):

        """

        :type nums: List[int]

        :rtype: int

        """

        counter_dict = {}

        

        for i in range(len(nums)):

            if nums[i] in counter_dict:

                counter_dict[nums[i]] = counter_dict[nums[i]] + 1

            else:

                counter_dict[nums[i]] = 1

        

        #print(counter_dict)

        found_key =None

        for j ,y in counter_dict.items():

            if y == 1:

                found_key = j 

                break

        

        return(found_key)

        Solution Do not know its right way  todo  or not  but i used solution like counts each elements occurrence using dict and then we travese through  dict my  using items and key ,value and match the target key  once it found we update the variable found_key  and just return it