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#include <algorithm>
#include <fstream>
#include <iostream>
#include <map>
#include <string>
#include <vector>
using namespace std;
vector<tuple<char, size_t, size_t>>
read_file(string_view filename)
{
fstream input{ filename };
vector<tuple<char, size_t, size_t>> instr;
for ( string line; getline(input, line); ) {
size_t value_a = 0;
size_t value_b = 0;
if ( sscanf(line.c_str(), "rect %zu x %zu", &value_a, &value_b) == 2 ) {
instr.emplace_back('r', value_a, value_b);
}
else if ( sscanf(line.c_str(), "rotate column x=%zu by %zu", &value_a, &value_b) == 2 ) {
instr.emplace_back('x', value_a, value_b);
}
else if ( sscanf(line.c_str(), "rotate row y=%zu by %zu", &value_a, &value_b) == 2 ) {
instr.emplace_back('y', value_a, value_b);
}
}
return instr;
}
void
solve(const vector<tuple<char, size_t, size_t>>& instr)
{
static const size_t width = 50;
static const size_t height = 6;
map<tuple<size_t, size_t>, char> disp;
auto reverse_y = [&](const size_t y, size_t lhs, size_t rhs) {
while ( lhs < rhs ) {
swap(disp[{ lhs++, y }], disp[{ --rhs, y }]);
}
};
auto rotate_y = [&](const size_t y, const size_t num) {
reverse_y(y, 0, width);
reverse_y(y, 0, num);
reverse_y(y, num, width);
};
auto reverse_x = [&](const size_t x, size_t lhs, size_t rhs) {
while ( lhs < rhs ) {
swap(disp[{ x, lhs++ }], disp[{ x, --rhs }]);
}
};
auto rotate_x = [&](const size_t x, const size_t num) {
reverse_x(x, 0, height);
reverse_x(x, 0, num);
reverse_x(x, num, height);
};
for ( const auto& [chr, val_a, val_b]: instr ) {
if ( chr == 'r' ) {
for ( size_t x = 0; x != val_a; ++x ) {
for ( size_t y = 0; y != val_b; ++y ) {
disp[{ x, y }] = '#';
}
}
}
else if ( chr == 'x' ) {
rotate_x(val_a, val_b);
}
else if ( chr == 'y' ) {
rotate_y(val_a, val_b);
}
}
// part1
cout << count_if(disp.begin(), disp.end(), [](auto pos) { return pos.second == '#'; }) << endl;
// part2
for ( size_t y = 0; y != height; ++y ) {
for ( size_t x = 0; x != width; ++x ) {
cout << ((disp[{ x, y }] == '#') ? '#' : ' ');
}
cout << endl;
}
cout << endl;
}
int
main()
{
auto instr = read_file("data/day08.txt");
solve(instr);
}
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