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#include "aoc.h"
namespace aoc2019 {
bool cross(const wire::line& lh, const wire::line& lv, day3point* p) {
auto in_range = [](int x, int a, int b) {
int min = std::min(a, b);
int max = std::max(a, b);
return x >= min && x <= max;
};
bool b1 = in_range(lv.a.x, lh.a.x, lh.b.x);
bool b2 = in_range(lh.a.y, lv.a.y, lv.b.y);
if (b1 && b2) {
*p = {lv.a.x, lh.a.y};
return true;
}
return false;
}
void match(const std::vector<wire::line>& lhs, const std::vector<wire::line>& lvs, day3point* p) {
for (auto& lh : lhs) {
for (auto& lv : lvs) {
if (cross(lh, lv, p)) {
return;
}
}
}
}
int day3(line_view file) {
wire ws[2];
day3point mp{0, 0};
int i{0};
per_line(file, [&ws, &mp, &i](line_view lv) {
day3point cp{0, 0};
ws[i++].parse(lv, &cp, &mp);
return true;
});
ws[0].sort();
ws[1].sort();
day3point p1;
day3point p2;
match(ws[0].psh, ws[1].psv, &p1);
match(ws[1].psh, ws[0].psv, &p2);
day3point p = std::min(p1, p2);
return p.distance() ;
}
} // namespace aoc2019
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