Advent2021/Day 6/Marcus/cpp/part2.cpp

#include <iostream>

using namespace std;

int main()
{
    int next_fish;
    unsigned long long fish[9] = {0};
    for(int i = 0; i < 300; i++)
    {
        cin >> next_fish;
        fish[next_fish]++;
    }
    
    unsigned long long total_fish = 300;
    for(int i = 0; i < 256; i++)
    {
        unsigned long long spawning_fish = fish[0];
        total_fish += spawning_fish;
        
        for(int j = 1; j < 9; j++)
        {
            fish[j-1] = fish[j];
        }
        
        fish[6] += spawning_fish;
        fish[8] = spawning_fish;
    }
    
    cout << total_fish << endl;
    
    return 0;
}