67 lines
1.8 KiB
C++
67 lines
1.8 KiB
C++
#include <fstream>
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#include <iostream>
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#include <sstream>
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#include <vector>
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std::vector<int> getFish(const std::string &file_name) {
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std::vector<int> fish;
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std::ifstream file(file_name);
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std::string str;
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std::getline(file, str);
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int tmp{};
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char tmp_char{};
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std::stringstream ss(str);
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while (ss >> tmp) {
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fish.push_back(tmp);
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ss >> tmp_char;
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}
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return fish;
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}
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uint64_t computeFish(std::vector<int> fish, int lifecycle, int young_addition,
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int days) {
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// index of bucket = days until reproduction
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std::vector<uint64_t> fish_buckets{};
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for (int i = 0; i < lifecycle + young_addition; i++) {
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fish_buckets.push_back(0);
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}
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for (auto &f : fish) {
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fish_buckets[f] += 1;
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}
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for (int i = 0; i < days; i++) {
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auto new_fish = fish_buckets[0];
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for (int j = 1; j < fish_buckets.size(); j++) {
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fish_buckets[j - 1] = fish_buckets[j];
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}
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fish_buckets[lifecycle - 1] += new_fish;
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fish_buckets.back() = new_fish;
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}
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uint64_t population = 0;
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for (auto &f : fish_buckets) {
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population += f;
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}
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return population;
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}
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uint64_t part1(const std::vector<int> &fish) {
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return computeFish(fish, 7, 2, 80);
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}
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uint64_t part2(const std::vector<int> &fish) {
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return computeFish(fish, 7, 2, 256);
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}
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int main(int argc, char **argv) {
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if (argc < 2) {
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std::cerr << "You must provide input file!" << std::endl;
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return 1;
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}
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auto fish = getFish(argv[1]);
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std::cout << "The number of fish after 80 days is \033[91;1m" << part1(fish)
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<< "\033[0m." << std::endl;
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std::cout << "The number of fish after 256 days is \033[91;1m"
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<< part2(fish) << "\033[0m." << std::endl;
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return 0;
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}
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