58 lines
1.4 KiB
C++
58 lines
1.4 KiB
C++
//
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// Created by Matthew Gretton-Dann on 02/12/2021.
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//
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#include <iostream>
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#include <set>
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#include <string>
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enum Direction { north, east, south, west };
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using Location = std::pair<int, int>;
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auto main() -> int
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{
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std::string line;
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if (!std::getline(std::cin, line)) {
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std::cerr << "Failed to read line.\n";
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return 1;
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}
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std::set<Location> visited;
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Location current{0, 0};
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Location direction{0, 1};
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visited.insert(current);
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for (std::size_t pos{0}; pos < line.size(); pos += 2) {
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switch (line.at(pos)) {
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case 'L':
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direction = {-direction.second, direction.first};
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break;
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case 'R':
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direction = {direction.second, -direction.first};
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break;
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default:
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abort();
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}
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++pos;
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assert(pos < line.size());
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std::size_t idx{0};
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auto dist{static_cast<int>(std::stoul(line.substr(pos), &idx))};
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while (dist-- > 0) {
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current.first += direction.first;
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current.second += direction.second;
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if (visited.find(current) != visited.end()) {
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auto horiz = std::abs(current.first);
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auto vert = std::abs(current.second);
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std::cout << "We end up " << horiz << " + " << vert << " = " << horiz + vert
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<< " blocks away.\n";
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return 0;
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}
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visited.insert(current);
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}
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pos += idx;
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}
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std::cerr << "Didn't find an answer.\n";
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return 1;
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} |