Single Number II

Given an array of integers, every element appears thrice except for one which occurs once.

Find that element which does not appear thrice.

Note: Your algorithm should have a linear runtime complexity.

Could you implement it without using extra memory?

Input Format:

    First and only argument of input contains an integer array A

Output Format:

    return a single integer.


2 <= N <= 5 000 000  
0 <= A[i] <= INT_MAX

For Examples :

Example Input 1:
    A = [1, 2, 4, 3, 3, 2, 2, 3, 1, 1]
Example Output 1:
    4 occur exactly once
Example Input 2:
    A = [0, 0, 0, 1]
Example Output 2:
NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a doubt? Checkout Sample Codes for more details.
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