day 7

d07.cc

@@ -0,0 +1,162 @@
+#include <iostream>
+#include <vector>
+#include <map>
+
+using namespace std;
+
+enum FsNodeType {
+    NODE_DIR,
+    NODE_FILE
+};
+
+struct FsNode {
+    FsNodeType type;
+    string name;
+    unsigned size;
+};
+
+struct FsFile : FsNode {
+};
+
+struct FsDir : FsNode {
+    FsDir *parent;
+    map<string, FsNode *> entries;
+};
+
+void print_node(FsNode *node, unsigned depth = 0)
+{
+    for (unsigned i = 0; i < depth; i++) clog << "  ";
+    clog << "- " << node->name << " (";
+    switch (node->type) {
+    case NODE_DIR: clog << "dir"; break;
+    case NODE_FILE: clog << "file"; break;
+    }
+    clog << ", ";
+    clog << "size=" << node->size;
+    clog << ")" << endl;
+
+    if (node->type == NODE_DIR) {
+        FsDir *dir = (FsDir *)node;
+        for (auto e : dir->entries) print_node(e.second, depth + 1);
+    }
+}
+
+unsigned calc_size(FsDir &dir)
+{
+    unsigned size = 0;
+    for (auto e : dir.entries) {
+        FsNode *node = e.second;
+
+        if (!node->size && node->type == NODE_DIR) calc_size(*(FsDir *)node);
+        size += node->size;
+    }
+    dir.size = size;
+    return size;
+}
+
+FsDir parse()
+{
+    FsDir root;
+    root.type = NODE_DIR;
+    root.name = "/";
+    root.parent = NULL;
+
+    FsDir *dir = &root;
+    for (string line; getline(cin, line);) {
+        if (line.at(0) != '$' || line.at(1) != ' ') {
+            unsigned split = line.find(' ');
+            string first = line.substr(0, split);
+            string name = line.substr(split + 1);
+
+            if (first == "dir") {
+                FsDir *newdir = new FsDir;
+                newdir->type = NODE_DIR;
+                newdir->name = name;
+                newdir->size = 0;
+                newdir->parent = dir;
+                dir->entries[name] = newdir;
+            } else {
+                unsigned size = stoi(first);
+                FsFile *newfile = new FsFile;
+                newfile->type = NODE_FILE;
+                newfile->name = name;
+                newfile->size = size;
+                dir->entries[name] = newfile;
+            }
+        }
+
+        if (line.substr(2, 3) == "ls") {
+            // derp?
+        } else if (line.substr(2, 3) == "cd ") {
+            string name = line.substr(5);
+            if (name == "/") {
+                dir = &root;
+            } else if (name == "..") {
+                if (dir->parent) dir = dir->parent;
+            } else {
+                auto it = dir->entries.find(name);
+                if (it != dir->entries.end()) {
+                    FsNode *node = it->second;
+                    if (node->type == NODE_DIR) {
+                        dir = (FsDir *)node;
+                    }
+                }
+            }
+        }
+    }
+
+    calc_size(root);
+    //print_node(&root);
+    return root;
+}
+
+unsigned p1(const FsDir &dir)
+{
+    unsigned count = 0;
+    if (dir.size <= 100000) count += dir.size;
+    for (auto e : dir.entries) {
+        FsNode *node = e.second;
+        if (node->type == NODE_DIR) count += p1(*(FsDir *)node);
+    }
+    return count;
+}
+
+unsigned p2(const FsDir &dir, unsigned target = 0)
+{
+    if (!target) target = dir.size - 40000000;
+
+    unsigned smallest = 30000000;
+    if (dir.size >= target && dir.size < smallest) smallest = dir.size;
+
+    for (auto e : dir.entries) {
+        FsNode *node = e.second;
+        if (node->type == NODE_DIR) {
+            unsigned size = p2(*(FsDir *)node, target);
+            if (size >= target && size < smallest) smallest = size;
+        }
+    }
+    return smallest;
+}
+
+void free_input(FsDir &dir)
+{
+    for (auto e : dir.entries) {
+        FsNode *node = e.second;
+        if (node->type == NODE_DIR) {
+            FsDir *dir = (FsDir *)node;
+            free_input(*dir);
+            delete dir;
+        } else if (node->type == NODE_FILE) {
+            FsFile *file = (FsFile *)node;
+            delete file;
+        }
+    }
+}
+
+int main()
+{
+    auto input = parse();
+    cout << p1(input) << endl;
+    cout << p2(input) << endl;
+    free_input(input);
+}

d07_output.txt

@@ -0,0 +1,2 @@
+1783610
+4370655

template.cc

@@ -25,7 +25,7 @@ unsigned p2(const Input &input)
 
 int main()
 {
-    Input input = parse();
+    auto input = parse();
     cout << p1(input) << endl;
     cout << p2(input) << endl;
 }