From 9cc732f746b9af6d5fac63d2e06835cddad58842 Mon Sep 17 00:00:00 2001
From: Benjamin Kraft <benjamin.kraft@online.de>
Date: Wed, 7 Dec 2022 09:19:04 +0100
Subject: [PATCH] Day07

---
 src/days/07/Day07.cpp | 128 +++++++++++++++++++++++++++++++++++++++++-
 src/days/07/Day07.h   |  28 +++++++++
 2 files changed, 153 insertions(+), 3 deletions(-)

diff --git a/src/days/07/Day07.cpp b/src/days/07/Day07.cpp
index d89165a..0d252f4 100644
--- a/src/days/07/Day07.cpp
+++ b/src/days/07/Day07.cpp
@@ -1,9 +1,131 @@
 #include "Day07.h"
 
 Result Day07::Task1() {
-	return Day::Task1();
+	Dir* tree = parseTree();
+
+	set<Dir*> dirsBelow = tree->getAllDirsBelowSize(100000);
+	uint64_t sum = accumulate(dirsBelow.begin(), dirsBelow.end(), 0, [](uint64_t s, Dir* dir){
+		return s + dir->getSize();
+	});
+
+	delete tree;
+	return to_string(sum);
 }
 
 Result Day07::Task2() {
-	return Day::Task2();
-}
\ No newline at end of file
+	Dir* tree = parseTree();
+
+	uint64_t toBeFreed = 30000000 - (70000000 - tree->getSize());
+
+	set<Dir*> dirsAbove = tree->getAllDirsAboveSize(toBeFreed);
+	set<uint64_t> sizes;
+	std::transform(dirsAbove.begin(), dirsAbove.end(), inserter(sizes, sizes.begin()), [](Dir* dir){
+		return dir->getSize();
+	});
+	uint64_t result = *std::min_element(sizes.begin(), sizes.end());
+
+	delete tree;
+	return to_string(result);
+}
+
+Dir* Day07::parseTree() {
+	Dir* tree = new Dir("/", nullptr);
+	Dir* cwd = tree;
+
+	auto pos = input.begin() + 1;
+	while (pos < input.end()){
+		if (pos->starts_with('$')){
+			if (pos->substr(2, 2) == "ls"){
+				pos++;
+				while (pos < input.end() && !pos->starts_with('$')){
+					if (pos->starts_with("dir")){
+						string name = pos->substr(4);
+						cwd->items.insert(new Dir(name, cwd));
+					} else {
+						size_t ws = pos->find(' ');
+						uint64_t size = stoi(pos->substr(0, ws));
+						string name = pos->substr(ws + 1);
+						cwd->items.insert(new File(name, cwd, size));
+					}
+					pos++;
+				}
+				continue;
+			}
+			if (pos->substr(2, 2) == "cd"){
+				string name = pos->substr(5);
+				if (name == ".."){
+					cwd = cwd->parent;
+				} else if (name == "/"){
+					cwd = cwd->findRoot();
+				} else {
+					for (Item* item : cwd->items){
+						if (item->name == name){
+							if (Dir* d = dynamic_cast<Dir*>(item)){
+								cwd = d;
+								break;
+							}
+						}
+					}
+				}
+				pos++;
+			}
+		}
+	}
+
+	return tree;
+}
+
+Dir *Dir::findRoot() {
+	if (name == "/")
+		return this;
+	return parent->findRoot();
+}
+
+uint64_t Dir::getSize() {
+	return accumulate(items.begin(), items.end(), 0, [](uint64_t s, Item* item){
+		return s + item->getSize();
+	});
+}
+
+set<Dir*> Dir::getDirs() {
+	set<Dir*> dirs;
+	for (Item* item : items){
+		if (Dir* d = dynamic_cast<Dir*>(item))
+			dirs.insert(d);
+	}
+	return dirs;
+}
+
+set<Dir*> Dir::getAllDirsBelowSize(uint64_t maxSize) {
+	set<Dir*> result;
+
+	for (Dir* dir : getDirs()){
+		if (dir->getSize() <= maxSize)
+			result.insert(dir);
+		set<Dir*> sub = dir->getAllDirsBelowSize(maxSize);
+		result.insert(sub.begin(), sub.end());
+	}
+
+	return result;
+}
+
+set<Dir *> Dir::getAllDirsAboveSize(uint64_t minSize) {
+	set<Dir*> result;
+
+	for (Dir* dir : getDirs()){
+		if (dir->getSize() >= minSize)
+			result.insert(dir);
+		set<Dir*> sub = dir->getAllDirsAboveSize(minSize);
+		result.insert(sub.begin(), sub.end());
+	}
+
+	return result;
+}
+
+uint64_t File::getSize() {
+	return size;
+}
+
+uint64_t Item::getSize() {
+	return 0;
+}
diff --git a/src/days/07/Day07.h b/src/days/07/Day07.h
index 39f98fe..4bb7457 100644
--- a/src/days/07/Day07.h
+++ b/src/days/07/Day07.h
@@ -2,9 +2,37 @@
 
 #include "../../Day.h"
 
+struct Dir;
+
+struct Item {
+	Item(string name, Dir* parent) : name(name), parent(parent){};
+	string name;
+	Dir* parent;
+	virtual uint64_t getSize();
+};
+
+struct Dir : Item {
+	Dir(string name, Dir* parent) : Item(name, parent) {}
+	set<Item*> items;
+	Dir* findRoot();
+	uint64_t getSize();
+	set<Dir*> getDirs();
+	set<Dir*> getAllDirsBelowSize(uint64_t maxSize);
+	set<Dir*> getAllDirsAboveSize(uint64_t minSize);
+};
+
+struct File : Item {
+	File(string name, Dir* parent, uint64_t size) : Item(name, parent), size(size) {}
+	uint64_t size;
+	uint64_t getSize();
+};
+
 class Day07 : public Day {
 protected:
+
 	Result Task1() override;
 
 	Result Task2() override;
+
+	Dir* parseTree();
 };
\ No newline at end of file