From b6e660ac61a927e517b355cd8d20ddcabc3c9b75 Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Thu, 15 Dec 2022 08:15:23 -0500
Subject: day15: part 1 c++, partial part 2
---
day15/part1.cpp | 50 +++++++++++++++++++++++++++++++++++++++++++++++
day15/part2.cpp | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 110 insertions(+)
create mode 100644 day15/part1.cpp
create mode 100644 day15/part2.cpp
(limited to 'day15')
diff --git a/day15/part1.cpp b/day15/part1.cpp
new file mode 100644
index 0000000..fb53753
--- /dev/null
+++ b/day15/part1.cpp
@@ -0,0 +1,50 @@
+#include <cstdio>
+#include <iostream>
+#include <set>
+#include <string>
+
+constexpr long Y = 2000000;
+
+int main()
+{
+ std::set<int> xs;
+ std::set<int> bs;
+ long px, py, bx, by;
+
+ do {
+ std::string line;
+ std::getline(std::cin, line);
+ if (std::cin.eof())
+ break;
+
+ auto a = sscanf(line.c_str(),
+ "Sensor at x=%ld, y=%ld: closest beacon is at x=%ld, y=%ld",
+ &px, &py, &bx, &by);
+
+ std::cout << px << ' ' << py << ' ' << bx << ' ' << by;
+
+ if (by == Y)
+ bs.insert(bx);
+
+ long ic = std::abs(px - bx) + std::abs(py - by);
+
+ if (Y < py - ic || Y > py + ic)
+ continue;
+
+ long spr = (ic - std::abs(py - Y));
+ for (long j = 0; j <= spr; ++j) {
+ xs.insert(px + j);
+ xs.insert(px - j);
+ }
+
+ std::cout << " -> " << xs.size() << std::endl;
+ } while (1);
+
+ for (auto& b : bs)
+ xs.erase(b);
+
+ std::cout << "Part 1: " << xs.size() << std::endl;
+
+ return 0;
+}
+
diff --git a/day15/part2.cpp b/day15/part2.cpp
new file mode 100644
index 0000000..6a80e54
--- /dev/null
+++ b/day15/part2.cpp
@@ -0,0 +1,60 @@
+#include <cstdio>
+#include <iostream>
+#include <string>
+#include <vector>
+
+struct Sensor
+{
+ long x, y, power;
+
+ Sensor(long xx, long yy, long pp):
+ x(xx), y(yy), power(pp) {}
+};
+
+int main()
+{
+ std::vector<Sensor> sensors;
+ long px, py, bx, by;
+
+ do {
+ std::string line;
+ std::getline(std::cin, line);
+ if (std::cin.eof())
+ break;
+
+ auto a = sscanf(line.c_str(),
+ "Sensor at x=%ld, y=%ld: closest beacon is at x=%ld, y=%ld",
+ &px, &py, &bx, &by);
+
+ long power = std::abs(px - bx) + std::abs(py - by);
+ sensors.emplace_back(px, py, power);
+ } while (1);
+
+ std::cout << "# of sensors: " << sensors.size() << std::endl;
+
+ for (long y = 0; y <= 4000000; ++y) {
+ std::cout << "\r \r" << y;
+ fflush(stdout);
+ for (long x = 0; x <= 4000000; ++x) {
+ bool h = false;
+
+ for (auto& s : sensors) {
+ auto dist = std::abs(x - s.x) + std::abs(y - s.y);
+ if (dist <= s.power) {
+ long spr = (dist - std::abs(s.y - y));
+ x += spr - std::abs(s.x - x);
+ h = true;
+ break;
+ }
+ }
+
+ if (!h) {
+ std::cout << std::endl << x << ", " << y << std::endl;
+ return 0;
+ }
+ }
+ }
+
+ return 0;
+}
+
--
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