140 lines
3.0 KiB
C++
140 lines
3.0 KiB
C++
#include <fstream>
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#include <iostream>
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#include <set>
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#include <string>
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#include <vector>
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std::vector<int> ParseRow(auto begin, auto end)
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{
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std::vector<int> rtn_indexes;
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std::vector<int> values;
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// initialize list with the first value
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values.push_back(*begin);
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// iterate through the rest:
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for(auto i = begin + 1; i != end; ++i)
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{
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// if it's higher than the most recent one:
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const auto val = *i;
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if(val > values.back())
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{
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values.push_back(val);
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rtn_indexes.push_back(std::distance(begin, i));
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}
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}
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return rtn_indexes;
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}
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std::vector<int> ParseCol(auto begin, auto end, int col)
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{
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std::vector<int> rtn_indexes;
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std::vector<int> values;
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// initialize list with the first value
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values.push_back((*begin)[col]);
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// iterate through the rest:
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for(auto i = begin + 1; i != end; ++i)
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{
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// if it's higher than the most recent one:
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const auto val = (*i)[col];
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if(val > values.back())
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{
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values.push_back(val);
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rtn_indexes.push_back(std::distance(begin, i));
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}
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}
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return rtn_indexes;
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}
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int main()
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{
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std::ifstream ifs("data.txt");
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if(!ifs.is_open())
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{
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std::cerr << "Missing data.txt." << std::endl;
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return -1;
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}
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unsigned long total = 0;
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unsigned long total_pt2 = 0;
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std::vector<std::vector<int>> trees;
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// Parse:
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for(std::string line; std::getline(ifs, line); )
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{
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if(line == "")
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continue;
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trees.push_back({});
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for(const char &ch : line)
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trees.back().push_back(ch - '0');
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}
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std::set<std::pair<int, int>> visible_coordinates;
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for(auto y = 0; y < trees.size(); ++y)
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{
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visible_coordinates.insert({0,y});
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visible_coordinates.insert({trees[y].size()-1,y});
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}
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for(auto x = 1; x < trees[0].size() - 1; ++x)
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{
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visible_coordinates.insert({x,0});
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visible_coordinates.insert({x,trees.size()-1});
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}
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// left to right, right to left IN EACH ROW:
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std::vector<int> points;
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for(auto y = 1; y < trees.size() - 1; ++y)
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{
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// left to right:
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points = ParseRow(trees[y].begin(), trees[y].end());
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for(const auto &point : points)
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visible_coordinates.insert({point,y});
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// right to left:
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points = ParseRow(trees[y].rbegin(), trees[y].rend());
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for(const auto &point : points)
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visible_coordinates.insert({trees[y].size() - point - 1,y});
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}
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for(auto x = 1; x < trees.size() - 1; ++x)
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{
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// left to right:
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points = ParseCol(trees.begin(), trees.end(), x);
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for(const auto &point : points)
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visible_coordinates.insert({x,point});
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// right to left:
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points = ParseCol(trees.rbegin(), trees.rend(), x);
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for(const auto &point : points)
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visible_coordinates.insert({x, trees.size() - point - 1});
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}
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total += visible_coordinates.size();
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for(auto y = 0; y < trees.size(); ++y)
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{
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for(auto x = 0; x < trees[y].size(); ++x)
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{
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if(visible_coordinates.contains({x,y}))
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std::cout << "\033[1;31m";
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else
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std::cout << "\033[0m";
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std::cout << trees[y][x];
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}
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std::cout << std::endl;
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}
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std::cout << "\033[0m";
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std::cout << " Total: " << total << std::endl;
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std::cout << "PT2 Total: " << total_pt2 << std::endl;
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return 0;
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}
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