Day14

src/days/14/Day14.cpp

@@ -1,9 +1,115 @@
 #include "Day14.h"
 
 Result Day14::Task1() {
-	return Day::Task1();
+	size_t lowestY;
+	Cave cave = parseCave(lowestY);
+
+	uint64 sandUnits = 0;
+	Point start = {500, 0};
+	while (true){
+		Point pos = start;
+		while (true){
+			if (cave[{pos.first, pos.second + 1}]){
+				if (cave[{pos.first - 1, pos.second + 1}]){
+					if (cave[{pos.first + 1, pos.second + 1}]){
+						cave[{pos}] = true;
+						break;
+					} else {
+						pos.first++;
+						pos.second++;
+					}
+				} else {
+					pos.first--;
+					pos.second++;
+				}
+			} else {
+				pos.second++;
+			}
+			if (pos.second > lowestY)
+				break;
+		}
+		if (pos.second > lowestY)
+			break;
+
+		sandUnits++;
+	}
+
+	return to_string(sandUnits);
 }
 
 Result Day14::Task2() {
-	return Day::Task2();
-}
+	size_t lowestY;
+	Cave cave = parseCave(lowestY);
+	lowestY += 2;
+
+	uint64 sandUnits = 0;
+	Point start = {500, 0};
+	while (true){
+		Point pos = start;
+		while (true){
+			if (pos.second + 1 == lowestY){
+				cave[pos] = true;
+				break;
+			}
+			if (cave[{pos.first, pos.second + 1}]){
+				if (cave[{pos.first - 1, pos.second + 1}]){
+					if (cave[{pos.first + 1, pos.second + 1}]){
+						cave[{pos}] = true;
+						break;
+					} else {
+						pos.first++;
+						pos.second++;
+					}
+				} else {
+					pos.first--;
+					pos.second++;
+				}
+			} else {
+				pos.second++;
+			}
+		}
+		sandUnits++;
+
+		if (pos == start)
+			break;
+	}
+
+	return to_string(sandUnits);
+}
+
+Day14::Cave Day14::parseCave(size_t &low) {
+	Cave cave;
+	low = 0;
+
+	for (const string &line : input){
+		size_t pos = 0;
+		size_t lastX, lastY;
+		while (pos < line.size()){
+			size_t commaPos = line.find(',', pos);
+			size_t minusPos = line.find('-', pos);
+			size_t newX = stoi(line.substr(pos, commaPos - pos));
+			size_t newY = stoi(line.substr(commaPos + 1, minusPos - 2 - commaPos));
+			if (minusPos == string::npos){
+				newY = stoi(line.substr(commaPos + 1));
+				minusPos = line.size();
+			}
+
+			using std::min, std::max;
+			if (pos > 0){
+				for (size_t x = min(lastX, newX); x <= max(lastX, newX); x++)
+					for (size_t y = min(lastY, newY); y <= max(lastY, newY); y++)
+						cave[{x, y}] = true;
+			}
+
+			if (newY > low)
+				low = newY;
+
+			lastX = newX;
+			lastY = newY;
+
+			pos = minusPos + 3;
+		}
+	}
+
+	return cave;
+}

src/days/14/Day14.h

@@ -3,6 +3,11 @@
 #include "../../Day.h"
 
 class Day14 : public Day {
+
+	typedef pair<size_t, size_t> Point;
+	typedef map<Point, bool> Cave;
+	Cave parseCave(size_t&);
+
 protected:
 	Result Task1() override;