Défi de programmation Count Pairs With a Sum

Problème

Count the pairs of different positions i < j in numbers where numbers[i] + numbers[j] equals target. Use two nested loops.

Implement count_pairs_with_sum(numbers, target).

numbers: The list of integers. target: The sum to look for.

Return the number of pairs.

0 ≤ length of numbers ≤ 500; -10,000 ≤ each number, target ≤ 10,000

Exemple 1

Entrée :
target = 6
numbers = [1, 5, 3, 3, 4]

Sortie attendue :
expected = 2

Entrée :
long long target = 6;
std::vector<long long> numbers = {1, 5, 3, 3, 4};

Sortie attendue :
long long expected = 2;

Entrée :
long target = 6;
long[] numbers = new long[] {1, 5, 3, 3, 4};

Sortie attendue :
long expected = 2;

1 + 5, 3 + 3 (the two 3s at different positions) make 6: 2 pairs.

Exemple 2

Entrée :
target = 4
numbers = [2, 2, 2]

Sortie attendue :
expected = 3

Entrée :
long long target = 4;
std::vector<long long> numbers = {2, 2, 2};

Sortie attendue :
long long expected = 3;

Entrée :
long target = 4;
long[] numbers = new long[] {2, 2, 2};

Sortie attendue :
long expected = 3;

Every pair of the three 2s sums to 4: positions (0,1), (0,2), (1,2) = 3 pairs.

Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.