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#include <fstream>
#include <iostream>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
vector<string>
read_file(const string& filename)
{
fstream input{ filename };
vector<string> lines;
for ( string line; getline(input, line); ) {
lines.emplace_back(line);
}
return lines;
}
void
part1(const vector<string>& lines)
{
long sum = 0;
for ( const auto& line: lines ) {
long found_inner = 0;
long found_outer = 0;
bool inner = false;
for ( size_t i = 0; i + 3 < line.length(); ++i ) {
if ( line[i] == '[' ) {
inner = true;
}
if ( line[i] == ']' ) {
inner = false;
}
if ( line[i + 0] == line[i + 3] && line[i + 0] != line[i + 1] && line[i + 1] == line[i + 2] ) {
if ( inner ) {
++found_inner;
}
else {
++found_outer;
}
}
}
sum += (found_inner == 0 && found_outer != 0) ? 1 : 0;
}
cout << sum << endl;
}
void
part2(const vector<string>& lines)
{
long sum = 0;
for ( const auto& line: lines ) {
set<tuple<char, char>> inners;
set<tuple<char, char>> outers;
bool inner = false;
for ( size_t i = 0; i + 2 < line.length(); ++i ) {
if ( line[i] == '[' ) {
inner = true;
}
if ( line[i] == ']' ) {
inner = false;
}
if ( line[i + 0] == line[i + 2] && line[i + 0] != line[i + 1] ) {
if ( inner ) {
inners.emplace(line[i + 0], line[i + 1]);
if ( outers.contains({ line[i + 1], line[i + 0] }) ) {
++sum;
break;
}
}
else {
outers.emplace(line[i + 0], line[i + 1]);
if ( inners.contains({ line[i + 1], line[i + 0] }) ) {
++sum;
break;
}
}
}
}
}
cout << sum << endl;
}
int
main()
{
auto lines = read_file("data/day07.txt");
part1(lines);
part2(lines);
}
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