155 lines
3.3 KiB
C++
155 lines
3.3 KiB
C++
#include <fstream>
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#include <iostream>
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#include <set>
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#include <string>
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#include <vector>
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enum Command {
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NOOP = 1,
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ADDX,
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};
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Command ParseCommand(const std::string &str) {
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if(str.size() < 4)
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return Command::NOOP;
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std::string head = str.substr(0, 4);
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if(head == "noop")
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return Command::NOOP;
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else if(head == "addx")
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return Command::ADDX;
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std::cerr << "Missing command type \"" << head << "\"." << std::endl;
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exit(-1);
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}
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void StepCycles(long &cycle, const Command &command, const long &x);
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void IncrementAndDraw(const long &x, long &cycle);
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long Report(const long &cycle, const long &x);
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void ApplyAction(const std::pair<Command, std::string> &command, long &x);
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int main()
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{
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std::ifstream ifs("data.txt");
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if(!ifs.is_open())
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{
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std::cerr << "Missing data.txt." << std::endl;
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return -1;
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}
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unsigned long total = 0;
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unsigned long total_pt2 = 0;
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std::vector<std::pair<Command, std::string> > commands;
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for(std::string line; std::getline(ifs, line); )
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{
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if(line == "")
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continue;
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auto cmd = ParseCommand(line);
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if(cmd == Command::NOOP)
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commands.push_back({cmd, ""});
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else
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commands.push_back({cmd, line.substr(5)});
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}
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long cycle = 1;
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long x = 1;
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for(const auto &command : commands)
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{
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// Step 1: Increase cycle count of command to see if we would have reported
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StepCycles(cycle, command.first, x);
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// Step 2: Report, if needed:
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total += Report(cycle, x);
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// Step 3: Perform command action:
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ApplyAction(command, x);
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}
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while(cycle <= 220)
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{
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StepCycles(cycle, Command::NOOP, x);
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total += Report(cycle, x);
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}
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std::cout << "Ended on cycle #" << cycle << ", value of x: " << x << std::endl;
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std::cout << " Total: " << total << std::endl;
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std::cout << "PT2 Total: " << total_pt2 << std::endl;
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return 0;
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}
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void StepCycles(long &cycle, const Command &command, const long &x)
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{
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switch(command)
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{
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case Command::NOOP:
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IncrementAndDraw(x, cycle);
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break;
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case Command::ADDX:
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for(auto i = 0; i < 2; ++i)
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IncrementAndDraw(x, cycle);
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break;
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default:
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std::cerr << "Missing ability to parse command type." << std::endl;
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exit(-1);
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break;
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};
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}
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long Report(const long &cycle, const long &x)
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{
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static long last_reported_cycle = -20;
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auto next_cycle = last_reported_cycle + 40;
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if(cycle > next_cycle)
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{
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// std::cout << "Cycle #" << next_cycle << ": "
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// << next_cycle << " * " << x << " = "
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// << next_cycle * x << std::endl;
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last_reported_cycle += 40;
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return next_cycle * x;
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}
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return 0; // no change
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}
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void ApplyAction(const std::pair<Command, std::string> &command, long &x)
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{
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switch(command.first)
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{
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case Command::NOOP:
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// std::cout << "NOOP" << std::endl;
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// noop
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break;
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case Command::ADDX:
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// std::cout << "ADDX " << command.second << ": x goes from " << x << " to ";
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x += std::atoi(command.second.c_str());
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// std::cout << x << std::endl;
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break;
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default:
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std::cerr << "Missing ability to parse command type." << std::endl;
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exit(-1);
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break;
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};
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}
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void IncrementAndDraw(const long &x, long &cycle)
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{
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static int drawing_index = 1; // 1 to 40
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// NOTE(dev): using -0 and +2 instead of -1 and +1 to account for 0-based vs 1-based
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if(drawing_index >= x - 0 && drawing_index <= x + 2) // within one or on target
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std::cout << "#";
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else
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std::cout << ".";
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++cycle;
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if(++drawing_index > 40)
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{
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std::cout << std::endl;
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drawing_index = 1;
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}
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}
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