bert/adventofcode
1
0
Fork 0
mirror of https://github.com/bertptrs/adventofcode.git synced 2025-12-25 21:00:31 +01:00
Code Issues Projects Releases Wiki Activity

Partial incorrect part 2.

Browse Source
This commit is contained in:
Bert Peters
2019-12-16 07:22:06 +01:00
parent 44f8108b1d
commit a5a0e6f860
1 changed files with 53 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
2019/src/day16.cpp
View File

@@ -25,6 +25,24 @@ namespace {
return result;
}
std::vector<int> advance(const std::vector<int>& numbers) {
std::vector<int> new_numbers;
new_numbers.reserve(numbers.size());
for (int rank = 0; rank < numbers.size(); ++rank) {
int n = 0;
for (int pos = rank; pos < numbers.size(); ++pos) {
n += get_modifier(rank, pos) * numbers[pos];
}
n = std::abs(n % 10);
new_numbers.push_back(n);
}
return new_numbers;
}
}
void aoc2019::day16_part1(std::istream &input, std::ostream &output) {
@@ -36,7 +54,7 @@ void aoc2019::day16_part1(std::istream &input, std::ostream &output) {
for (int rank = 0; rank < numbers.size(); ++rank) {
int n = 0;
for (int pos = 0; pos < numbers.size(); ++pos) {
for (int pos = rank; pos < numbers.size(); ++pos) {
n += get_modifier(rank, pos) * numbers[pos];
}
@@ -53,5 +71,38 @@ void aoc2019::day16_part1(std::istream &input, std::ostream &output) {
}
void aoc2019::day16_part2(std::istream &input, std::ostream &output) {
output << "Not implemented\n";
auto numbers = read_input(input);
const auto initial_size = numbers.size();
constexpr auto repetitions = 10000;
numbers.reserve(repetitions * numbers.size());
int offset = 0;
for (int i = 0; i < 7; ++i) {
offset *= 10;
offset += numbers[i];
}
for (int i = 1; i < repetitions; ++i) {
std::copy(numbers.begin(), numbers.begin() + initial_size, std::back_inserter(numbers));
}
numbers = std::vector(numbers.begin() + offset, numbers.end());
for (int i = 0; i < 100; ++i) {
std::vector<int> partial_sums(numbers.size());
std::vector<int> new_numbers(numbers.size());
partial_sums[0] = numbers[0];
for (int j = 1; j < numbers.size(); ++j) {
partial_sums[j] = partial_sums[j - 1] + numbers[j];
}
for (int j = 0; j < numbers.size(); ++j) {
new_numbers[j] = partial_sums.back() - partial_sums[j] + numbers[j];
}
}
std::copy(numbers.begin(), numbers.begin() + 8, std::ostream_iterator<int>(output));
}