92 lines
2.2 KiB
C++
92 lines
2.2 KiB
C++
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#include "intcode.hpp"
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#include <iostream>
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intcode::intcode() : rom_{}, ram_{}, pc_{0}, base_{0} {}
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intcode::intcode(std::vector<std::int64_t> ram) : rom_{ram}, ram_{}, pc_{0}, base_{0} {}
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auto intcode::ref(std::int64_t instruction, std::int64_t p, std::size_t offset) -> std::int64_t& {
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auto& i = at(pc_ + offset);
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switch (instruction / p % 10) {
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case 0: return at(i);
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case 1: return i;
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case 2: return at(base_ + i);
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default: throw BadInstruction{instruction};
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}
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}
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auto intcode::at(std::size_t i) -> std::int64_t& {
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return i < rom_.size() ? rom_[i] : ram_[i];
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}
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auto intcode::step() -> std::variant<Input, Output, Halt> {
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for (;;) {
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auto instruction = at(pc_);
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auto a = [this,instruction]() -> std::int64_t& { return ref(instruction, 100, 1); };
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auto b = [this,instruction]() -> std::int64_t& { return ref(instruction, 1000, 2); };
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auto c = [this,instruction]() -> std::int64_t& { return ref(instruction, 10000, 3); };
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switch (instruction % 100) {
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case 1:
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c() = a() + b();
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pc_ += 4;
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break;
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case 2:
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c() = a() * b();
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pc_ += 4;
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break;
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case 3: {
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auto& pos = a();
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pc_ += 2;
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return Input{pos};
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}
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case 4: {
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auto val = a();
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pc_ += 2;
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return Output{val};
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}
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case 5:
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pc_ = a() ? b() : pc_ + 3;
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break;
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case 6:
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pc_ = a() ? pc_ + 3 : b();
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break;
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case 7:
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c() = a() < b();
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pc_ += 4;
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break;
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case 8:
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c() = a() == b();
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pc_ += 4;
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break;
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case 9:
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base_ += a();
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pc_ += 2;
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break;
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case 99:
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return Halt{};
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default:
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throw BadInstruction{instruction};
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}
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}
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}
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auto parse_stream(std::istream& in) -> std::vector<std::int64_t> {
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std::int64_t x;
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std::string str;
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std::vector<std::int64_t> result;
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while(std::getline(in, str, ',')) {
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result.push_back(std::stoi(str));
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}
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return result;
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}
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