Thraix
92 lines
2.2 KiB
C++
92 lines
2.2 KiB
C++
#include "common/aoc.h"
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namespace y2021::day09
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{
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REGISTER_DAY(2021, Day09, Array2D<int>, int);
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REGISTER_TEST_EXAMPLE(2021, Day09, ExampleInput, 1, 15);
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REGISTER_TEST(2021, Day09, Input, 1, 478);
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REGISTER_TEST_EXAMPLE(2021, Day09, ExampleInput, 2, 1134);
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REGISTER_TEST(2021, Day09, Input, 2, 1327014);
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READ_INPUT(input)
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{
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return Input::ReadDigitsAsArray2D(input);
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}
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OUTPUT1(input)
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{
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int count = 0;
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Index2D index{0, 0};
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for (auto& val : input)
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{
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Index2D indices[4]{
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{index.x - 1, index.y}, {index.x, index.y - 1}, {index.x + 1, index.y}, {index.x, index.y + 1}};
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bool all = true;
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for (auto& ind : indices)
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{
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if (input.IsInside(ind) && input[ind] <= val)
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{
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all = false;
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break;
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}
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}
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if (all)
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count += val + 1;
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input.Increment(index);
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}
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return count;
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}
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OUTPUT2(input)
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{
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std::vector<Index2D> basins;
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Index2D index{0, 0};
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for (auto& val : input)
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{
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Index2D indices[4]{
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{index.x - 1, index.y}, {index.x, index.y - 1}, {index.x + 1, index.y}, {index.x, index.y + 1}};
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bool all = true;
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for (auto& ind : indices)
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{
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if (input.IsInside(ind) && input[ind] <= val)
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{
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all = false;
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break;
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}
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}
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if (all)
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basins.emplace_back(index);
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input.Increment(index);
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}
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std::vector<int> numbers;
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for (auto&& basin : basins)
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{
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std::stack<Index2D> stack;
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std::set<Index2D> visited;
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stack.emplace(basin);
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visited.emplace(basin);
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while (!stack.empty())
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{
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auto index = stack.top();
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stack.pop();
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Index2D indices[4]{
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{index.x - 1, index.y}, {index.x, index.y - 1}, {index.x + 1, index.y}, {index.x, index.y + 1}};
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for (auto&& ind : indices)
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{
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if (input.IsInside(ind) && input[ind] != 9 && visited.find(ind) == visited.end())
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{
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stack.emplace(ind);
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visited.emplace(ind);
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}
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}
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}
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numbers.emplace_back(visited.size());
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}
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std::sort(numbers.begin(), numbers.end());
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return numbers[numbers.size() - 1] * numbers[numbers.size() - 2] * numbers[numbers.size() - 3];
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}
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}
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