Find The Parity Outlier

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You are given an array (which will have a length of at least 3, but could be very large) containing integers. The array is either entirely comprised of odd integers or entirely comprised of even integers except for a single integer N. Write a method that takes the array as an argument and returns this “outlier” N.

Examples
[2, 4, 0, 100, 4, 11, 2602, 36] –> 11 (the only odd number)

[160, 3, 1719, 19, 11, 13, -21] –> 160 (the only even number)

blessedtechie

This problem brings back memories of a classic computer science homework: identifying the outlier in a list of numbers. Here's a clever solution that leverages the parity (even or odd) of the first few elements.

Parity Check: We start by examining the parity of the first three numbers in the list. Even numbers result in a remainder of 0 when divided by 2, while odds yield a remainder of 1.
Majority Rules: By storing these remainders in a list, we can determine the prevailing parity (even or odd) in the majority.
Find the Outlier: Finally, we iterate through the entire list. The first number whose parity doesn't match the majority is our outlier!

This approach offers an efficient way to pinpoint the outlier, making it a valuable technique to have in your problem-solving toolbox.

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Outlier in an array is a very good interview question too, it will get you sweating a bit. No, did I say good? I meant terrible!