64 lines
1.5 KiB
C++
64 lines
1.5 KiB
C++
//
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// Created by Matthew Gretton-Dann on 04/12/2021.
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//
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#include <array>
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#include <iostream>
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#include <string>
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#include <vector>
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auto aba(std::string const& line) -> bool
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{
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enum State { outside, inside };
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using AbaArray = std::array<char, 2>;
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std::vector<AbaArray> abas;
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std::vector<AbaArray> pending_abas;
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State state{outside};
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for (std::size_t idx{0}; idx < line.size() - 2; ++idx) {
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if (line[idx] == '[') {
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state = inside;
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}
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else if (line[idx] == ']') {
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state = outside;
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}
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else if (line[idx] != line[idx + 1] && line[idx] == line[idx + 2]) {
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if (state == outside) {
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char a{line[idx]};
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char b{line[idx + 1]};
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abas.push_back({a, b});
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if (std::find_if(pending_abas.begin(), pending_abas.end(), [a, b](auto const& it) {
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return it[0] == a && it[1] == b;
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}) != pending_abas.end()) {
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return true;
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}
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}
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else {
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char b{line[idx]};
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char a{line[idx + 1]};
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if (std::find_if(abas.begin(), abas.end(), [a, b](auto const& it) {
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return it[0] == a && it[1] == b;
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}) != abas.end()) {
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return true;
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}
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pending_abas.push_back({a, b});
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}
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}
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}
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return false;
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}
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auto main() -> int
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{
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std::string line;
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unsigned good_count{0};
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while (std::getline(std::cin, line)) {
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if (aba(line)) {
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++good_count;
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}
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}
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std::cout << "ABBA lines that support SSL: " << good_count << '\n';
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return 0;
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}
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