128 lines
4.1 KiB
C++
128 lines
4.1 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 "../misc/types.hpp"
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#include "../misc/print.hpp"
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auto evaluate_part1(const std::string & equation, usize & index) -> u64 {
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auto value = u64(0);
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auto operation = 0;
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while (equation[index] != ')') {
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if ('0' <= equation[index] && equation[index] <= '9') {
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auto end = index;
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while ('0' <= equation[++end] && equation[end] <= '9');
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if (operation == 0) {
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value += std::stoll(equation.substr(index, end - index));
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} else {
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value *= std::stoll(equation.substr(index, end - index));
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}
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index = end;
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} else if (equation[index] == '+') {
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operation = 0;
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index += 2;
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} else if (equation[index] == '*') {
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operation = 1;
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index += 2;
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} else if (equation[index] == '(') {
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if (operation == 0) {
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value += evaluate_part1(equation, ++index);
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} else {
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value *= evaluate_part1(equation, ++index);
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}
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} else if (equation[index] == ' ') {
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++index;
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}
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}
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++index;
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return value;
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}
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auto evaluate_part2(const std::string & equation, usize & index) -> u64;
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auto evaluate_part2_addition(const std::string & equation, usize & index) -> u64;
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auto evaluate_part2_factor(const std::string & equation, usize & index) -> u64;
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auto evaluate_part2(const std::string & equation, usize & index) -> u64 {
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auto value1 = evaluate_part2_addition(equation, index);
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if (++index < equation.size() && equation[index] == '*') {
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auto value2 = evaluate_part2(equation, index += 2);
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return value1 * value2;
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}
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--index;
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return value1;
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}
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auto evaluate_part2_addition(const std::string & equation, usize & index) -> u64 {
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auto value1 = evaluate_part2_factor(equation, index);
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if (++index < equation.size() && equation[index] == '+') {
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auto value2 = evaluate_part2_addition(equation, index += 2);
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return value1 + value2;
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}
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--index;
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return value1;
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}
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auto evaluate_part2_factor(const std::string & equation, usize & index) -> u64 {
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auto value = u64(0);
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if (equation[index] == '(') {
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value = evaluate_part2(equation, ++index);
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++index;
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} else {
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auto end = index;
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while ('0' <= equation[++end] && equation[end] <= '9');
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value = std::stoll(equation.substr(index, end - index));
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index = end;
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}
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return value;
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}
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auto day18() -> void {
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auto equations = std::vector<std::string>();
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{
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auto line = std::string();
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auto file = std::ifstream("inputs/day18.input");
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while (getline(file, line)) {
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equations.push_back(line + ')');
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}
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}
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auto sum = u64(0);
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for (auto i = usize(0); i < equations.size(); ++i) {
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auto index = usize(0);
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sum += evaluate_part1(equations[i], index);
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}
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print(sum);
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sum = u64(0);
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for (auto i = usize(0); i < equations.size(); ++i) {
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auto index = usize(0);
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sum += evaluate_part2_factor('(' + equations[i], index);
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}
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print(sum);
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}
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