pootzko
12/21/2016 - 2:43 PM

## Translation for: https://gist.github.com/gameguy43/c4bb482652d62e31d1bee9d09e331999

``````public int highestProductOf3(int[] arrayOfInts)
{
if (arrayOfInts.Length < 3)
{
throw new ArgumentException("Less than 3 items!");
}

// Firstly we will separate specific array elements
// into their own variables for better clarity and maintainability.
// Working directly with specific array elements is generally
// it's hard to manage and refactor.
int first = arrayOfInts[0];
int second = arrayOfInts[1];
int third = arrayOfInts[2];

// We're going to start at the 3rd item (at index 2)
// so pre-populate highests and lowests based on the first 2 items.
// We could also start these as null and check below if they're set
// but this is arguably cleaner.
int highest = Math.Max(first, second);
int lowest = Math.Min(first, second);

int highestProductOf2 = first * second;
int lowestProductOf2 = first * second;

// Except this one - we pre-populate it for the first /3/ items.
// This means in our first pass it'll check against itself, which is fine.
int highestProductOf3 = first * second * third;

// Walk through items, starting at index 2.
for (var i = 2; i < arrayOfInts.Length; i++)
{
int current = arrayOfInts[i];

// Do we have a new highest product of 3?
// It's either the current highest,
// or the current times the highest product of two
// or the current times the lowest product of two.
highestProductOf3 = new int[] {
highestProductOf3,
current * highestProductOf2,
current * lowestProductOf2
}.Max();

// Do we have a new highest product of two?
highestProductOf2 = new int[] {
highestProductOf2,
current * highest,
current * lowest
}.Max();

// Do we have a new lowest product of two?
lowestProductOf2 = new int[] {
lowestProductOf2,
current * highest,
current * lowest
}.Max();

// Do we have a new highest?
highest = Math.Max(highest, current);

// Do we have a new lowest?
lowest = Math.Min(lowest, current);
}

return highestProductOf3;
}``````