find_if_sum_is_in_array.dart

void main() {
  findIfSumIsInArray();
}

/**
 Given a list of numbers and a number k, return whether any two numbers from the list add up to k.

    For example, given [10, 15, 3, 7] and k of 17, return true since 10 + 7 is 17.

    Bonus: Can you do this in one pass?
 **/
void findIfSumIsInArray() {

  List<int> input = [10, -6, 5, 1, 33];
  int value = 27;

  print("Some $value was found: ${hasSum(input, value)}");
}

bool hasSum(List<int> ar, int sum) {
  Set<int> previousValues = {};
  for (var el in ar) {
    if (previousValues.contains(sum - el)) {
      return true;
    }
    previousValues.add(el);
  }
  return false;
}