113 lines
3.5 KiB
C++
113 lines
3.5 KiB
C++
/*******************************************************************************
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*
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* Copyright (c) 2020 Gnarwhal
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*
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* -----------------------------------------------------------------------------
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files(the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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*******************************************************************************/
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#include <vector>
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#include <string>
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#include <iostream>
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#include <fstream>
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#include "types.hpp"
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enum OpCode { Acc, Jmp, Nop };
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struct Op{ OpCode code; i32 num; };
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auto extract_op(const std::string & string) -> Op {
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auto op = Op{ Nop, 0 };
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auto op_code_str = string.substr(0, 3);
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if (string.substr(0, 3) == "acc") { op.code = Acc; }
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else if (string.substr(0, 3) == "jmp") { op.code = Jmp; }
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else if (string.substr(0, 3) == "nop") { op.code = Nop; }
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op.num = std::stoi(string.substr(4, string.size() - 4));
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return op;
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}
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struct State{ u32 isp; i32 acc; };
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auto execute(State & state, const std::vector<Op> & ops) -> void {
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switch (ops[state.isp].code) {
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case Acc: state.acc += ops[state.isp].num; ++state.isp; break;
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case Jmp: state.isp += ops[state.isp].num; break;
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case Nop: ++state.isp; break;
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}
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}
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auto attempt_swap(State & state, std::vector<Op> & ops) -> bool {
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if (ops[state.isp].code == Jmp) {
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ops[state.isp].code = Nop;
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} else if (ops[state.isp].code == Nop) {
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ops[state.isp].code = Jmp;
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} else {
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return false;
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}
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auto local_state = state;
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auto executed = std::vector<bool>(ops.size());
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while (local_state.isp < ops.size() && !executed[local_state.isp]) {
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executed[local_state.isp] = true;
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execute(local_state, ops);
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}
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if (local_state.isp >= ops.size()) {
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state = local_state;
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return true;
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} else if (ops[state.isp].code == Jmp) {
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ops[state.isp].code = Nop;
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} else if (ops[state.isp].code == Nop) {
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ops[state.isp].code = Jmp;
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}
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return false;
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}
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auto main(i32 argc, char * argv[]) -> i32 {
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auto ops = std::vector<Op>();
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{
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auto line = std::string();
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auto file = std::ifstream("day8.input");
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while (getline(file, line)) {
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ops.push_back(extract_op(line));
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}
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}
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auto state = State{ 0, 0 };
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auto executed = std::vector<bool>(ops.size());
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while (!executed[state.isp]) {
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executed[state.isp] = true;
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execute(state, ops);
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}
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std::cout << state.acc << std::endl;
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state = State{ 0, 0 };
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while (state.isp < ops.size()) {
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if (attempt_swap(state, ops)) {
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std::cout << state.acc << std::endl;
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break;
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}
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execute(state, ops);
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}
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return 0;
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}
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