hugomardbrink/aoc24
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Day 17

Browse source
This commit is contained in:
Hugo Mårdbrink 2024-12-17 22:11:16 +01:00
parent 37aabd15f1
commit 83867786a5
1 changed files with 199 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

201
d17/main.cxx
View file

@ -1,15 +1,208 @@
#include <string>
#include <sstream>
#include <chrono>
#include <iostream>
#include <fstream>
#include <unordered_map>
#include <functional>
#include <omp.h>
using std::cout, std::endl;
int main() {
std::ifstream file{"../d17/input.txt"};
constexpr const char content[] = {
#embed "input.txt"
};
enum class Opcode : int {
ADV = 0,
BXL,
BST,
JNZ,
BXC,
OUT,
BDV,
CDV
};
struct Registers {
uint64_t A;
uint64_t B;
uint64_t C;
uint64_t instruction_pointer;
std::string rstdout = "";
bool operator==(const Registers& other) const {
return A == other.A && B == other.B && C == other.C && instruction_pointer == other.instruction_pointer && rstdout == other.rstdout;
}
};
namespace std {
template <>
struct hash<Registers> {
std::size_t operator()(const Registers& regs) const {
return std::hash<uint64_t>{}(regs.A) ^ std::hash<uint64_t>{}(regs.B) ^ std::hash<uint64_t>{}(regs.C) ^ std::hash<std::string>{}(regs.rstdout);
}
};
}
constexpr uint64_t resolve_combo_operand(int operand, Registers& regs) {
switch(operand) {
case 0: return 0;
case 1: return 1;
case 2: return 2;
case 3: return 3;
case 4: return regs.A;
case 5: return regs.B;
case 6: return regs.C;
default: exit(-1);
};
}
std::unordered_map<Opcode, std::function<void(Registers& regs, int64_t operand)>> opcodes = {
{Opcode::ADV, [](Registers& regs, int64_t operand) {
regs.A /= std::pow(2, resolve_combo_operand(operand, regs));
regs.instruction_pointer += 2;
}},
{Opcode::BXL, [](Registers& regs, int64_t operand) {
regs.B ^= operand;
regs.instruction_pointer += 2;
}},
{Opcode::BST, [](Registers& regs, int64_t operand) {
regs.B = resolve_combo_operand(operand, regs) % 8;
regs.instruction_pointer += 2;
}},
{Opcode::JNZ, [](Registers& regs, int64_t operand) {
if(regs.A != 0) {
if(regs.instruction_pointer == operand) {
regs.instruction_pointer += 2;
} else {
regs.instruction_pointer = operand;
}
}
}},
{Opcode::BXC, [](Registers& regs, int64_t _) {
regs.B ^= regs.C;
regs.instruction_pointer += 2;
}},
{Opcode::OUT, [](Registers& regs, int64_t operand) {
auto val_str = std::to_string(resolve_combo_operand(operand, regs) % 8);
std::string to_print = "";
for(int i = 0; i < val_str.size(); i++) {
to_print += val_str[i];
to_print += ',';
}
regs.rstdout += to_print;
regs.instruction_pointer += 2;
}},
{Opcode::BDV, [](Registers& regs, int64_t operand) {
regs.B = regs.A / std::pow(2, resolve_combo_operand(operand, regs));
regs.instruction_pointer += 2;
}},
{Opcode::CDV, [](Registers& regs, int64_t operand) {
regs.C = regs.A / std::pow(2, resolve_combo_operand(operand, regs));
regs.instruction_pointer += 2;
}}
};
std::string part_1() {
std::istringstream input_stream(content);
std::string line;
while (std::getline(file, line)) {
Registers regs = {0, 0, 0, 0, ""};
std::getline(input_stream, line);
regs.A = std::stoll(line.substr(line.find(":") + 1));
std::getline(input_stream, line);
regs.B = std::stoll(line.substr(line.find(":") + 1));
std::getline(input_stream, line);
regs.C = std::stoll(line.substr(line.find(":") + 1));
std::vector<int> program;
getline(input_stream, line);
getline(input_stream, line, ' ');
while(getline(input_stream, line, ',')) {
if(!line.empty()) program.push_back(std::stoi(line));
}
auto prev_regs = regs;
while(regs.instruction_pointer < program.size()) {
auto opcode = static_cast<Opcode>(program[regs.instruction_pointer]);
auto operand = program[regs.instruction_pointer + 1];
opcodes[opcode](regs, operand);
if(prev_regs == regs) {
regs.rstdout.pop_back();
break;
}
prev_regs = regs;
}
return regs.rstdout;
}
uint64_t part_2() {
std::istringstream input_stream(content);
std::string line;
Registers target_regs = {0, 0, 0, 0, ""};
std::getline(input_stream, line);
target_regs.A = std::stoll(line.substr(line.find(":") + 1));
std::getline(input_stream, line);
target_regs.B = std::stoll(line.substr(line.find(":") + 1));
std::getline(input_stream, line);
target_regs.C = std::stoll(line.substr(line.find(":") + 1));
std::vector<int> program;
getline(input_stream, line);
getline(input_stream, line, ' ');
while(getline(input_stream, line, ',')) {
if(!line.empty()) program.push_back(std::stoi(line));
}
for(auto i : program) {
target_regs.rstdout += std::to_string(i) + ",";
}
target_regs.rstdout.pop_back();
uint64_t a_init = std::pow(8, 15);
while(a_init < std::pow(8, 16)){
Registers regs = {a_init, 0, 0, 0, ""};
auto prev_regs = regs;
while(regs.instruction_pointer < program.size()) {
auto opcode = static_cast<Opcode>(program[regs.instruction_pointer]);
auto operand = program[regs.instruction_pointer + 1];
opcodes[opcode](regs, operand);
if(prev_regs == regs) {
regs.rstdout.pop_back();
break;
}
prev_regs = regs;
}
if(regs.rstdout == target_regs.rstdout) {
break;
}
for(int i = 15; i >= 0; i--) {
if(regs.rstdout[i*2] != target_regs.rstdout[i*2]) {
a_init += std::pow(8, i);
break;
}
}
}
return a_init;
}
int main() {
std::chrono::steady_clock::time_point begin = std::chrono::steady_clock::now();
auto p1_val = part_1();
std::chrono::steady_clock::time_point middle = std::chrono::steady_clock::now();
auto p2_val = part_2();
std::chrono::steady_clock::time_point end = std::chrono::steady_clock::now();
cout << "Part 1: " << p1_val << " (" << std::chrono::duration_cast<std::chrono::microseconds>(middle - begin).count() << "µs)" << endl;
cout << "Part 2: " << p2_val << " (" << std::chrono::duration_cast<std::chrono::microseconds>(end - middle).count() << "µs)" << endl;
return 0;
}