Desafío de programación Array Average

Problema

Return the arithmetic mean of the list: its sum divided by its length, as a decimal number.

Implement array_average(numbers).

numbers: A non-empty list of integers.

Return the average.

1 ≤ length ≤ 100,000; -10⁹ ≤ each value ≤ 10⁹

Ejemplo 1

Entrada:
numbers = [2, 4, 6]

Salida esperada:
expected = 4.0

Entrada:
std::vector<long long> numbers = {2, 4, 6};

Salida esperada:
double expected = 4.0;

Entrada:
long[] numbers = new long[] {2, 4, 6};

Salida esperada:
double expected = 4.0;

(2 + 4 + 6) / 3 = 4.

Ejemplo 2

Entrada:
numbers = [1, 2]

Salida esperada:
expected = 1.5

Entrada:
std::vector<long long> numbers = {1, 2};

Salida esperada:
double expected = 1.5;

Entrada:
long[] numbers = new long[] {1, 2};

Salida esperada:
double expected = 1.5;

(1 + 2) / 2 = 1.5; divide as decimals.

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