46 lines
1.1 KiB
C++
46 lines
1.1 KiB
C++
//
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// Created by Matthew Gretton-Dann on 06/12/2021.
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//
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#include <iostream>
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#include <numeric>
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#include <string>
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#include <vector>
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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 << "Unable to read input.\n";
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return 1;
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}
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std::vector<std::uint64_t> fish(9, 0);
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for (auto c : line) {
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if (c == ',') {
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continue;
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}
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if (c >= '0' && c <= '8') {
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++fish.at(c - '0');
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}
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else {
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std::cerr << "Can't interpret " << c << '\n';
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return 1;
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}
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}
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constexpr unsigned days_wanted{256};
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for (unsigned day{0}; day < days_wanted; ++day) {
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std::vector<std::uint64_t> new_fish;
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std::copy(fish.begin() + 1, fish.end(), std::back_inserter(new_fish));
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new_fish.at(6) += fish.at(0);
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new_fish.push_back(fish.at(0));
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std::swap(fish, new_fish);
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}
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std::cout << "Fish count after " << days_wanted << " days: "
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<< std::accumulate(fish.begin(), fish.end(), std::uint64_t{0},
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[](auto a, auto b) { return a + b; })
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<< '\n';
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return 0;
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} |