solve day 7

Makefile

@@ -1,4 +1,4 @@
-main: main.c day*.c
+main: main.c day*.c vec.h aoc.h
 	gcc -o main main.c -lcurl
 
 run: main

day7.c

@@ -0,0 +1,167 @@
+#include <limits.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/param.h>
+
+#include "aoc.h"
+#include "vec.h"
+
+#define CD_CMD "$ cd"
+#define LS_CMD "$ ls"
+
+#define TOTAL_FS_SIZE 70000000
+#define UPDATE_SIZE 30000000
+
+struct TreeNode {
+	char *name;
+	struct TreeNode *parent;
+	struct TreeNode **children;
+	size_t children_count;
+	size_t size;
+};
+
+static struct TreeNode *append_node(struct TreeNode *parent, char *child_name, size_t size)
+{
+	struct TreeNode *new_child = calloc(1, sizeof(struct TreeNode));
+	new_child->parent = parent;
+	new_child->name = child_name;
+	new_child->size = size;
+
+	parent->children = realloc(parent->children, sizeof(struct TreeNode*)*(parent->children_count+1));
+	parent->children[parent->children_count] = new_child;
+	parent->children_count++;
+	return new_child;
+}
+
+static struct TreeNode *get_or_append_child(struct TreeNode *parent, char *child_name)
+{
+	for (int i = 0; i < parent->children_count; i++) {
+		struct TreeNode *child = parent->children[i];
+		if (strcmp(child->name, child_name) == 0) {
+			return child;
+		}
+	}
+
+	return append_node(parent, child_name, -1);
+}
+
+static int find_char(char *haystack, char needle) {
+	int n = strlen(haystack);
+	for (int i = 0; i < n; i++) {
+		if (haystack[i] == needle) {
+			return i;
+		}
+	}
+	return -1;
+}
+
+static void populate_directory_sizes(struct TreeNode *start)
+{
+	struct TreeNode *current = start;
+	while (current != start->parent) {
+		bool is_explored = true;
+		for (int i = 0; i < current->children_count; i++) {
+			struct TreeNode *child = current->children[i];
+			if (child->size == -1) {
+				current = child;
+				is_explored = false;
+				break;
+			}
+		}
+
+		if (is_explored) {
+			current->size = 0;
+			for (int i = 0; i < current->children_count; i++) {
+				current->size += current->children[i]->size;
+			}
+
+			current = current->parent;
+		}
+	}
+}
+
+static void *day7_parse(char **lines, int line_count)
+{
+	struct TreeNode *root = calloc(1, sizeof(struct TreeNode));
+	root->name = "/";
+
+	struct TreeNode *current = root;
+	for (int i = 0; i < line_count; i++) {
+		char *line = lines[i];
+		if (strncmp(line, CD_CMD, sizeof(CD_CMD)-1) == 0) {
+			char *dir_name = line + sizeof(CD_CMD);
+			if (strncmp(dir_name, "/", 1) == 0) {
+				current = root;
+			} else if (strncmp(dir_name, "..", 2) == 0) {
+				current = current->parent;
+			} else {
+				current = get_or_append_child(current, dir_name);
+			}
+		} else if (strncmp(line, LS_CMD, sizeof(LS_CMD)) == 0) {
+			continue;
+		} else {
+			if (strncmp(line, "dir", 3) == 0) {
+				char *dir_name = line + 4;
+				get_or_append_child(current, dir_name);
+			} else {
+				int sep = find_char(line, ' ');
+				char *child_name = line + sep + 1;
+				line[sep] = '\0';
+				int size = strtol(line, NULL, 10);
+				line[sep] = ' ';
+				append_node(current, child_name, size);
+			}
+		}
+	}
+
+	return root;
+}
+
+static void day7_part1(void *p)
+{
+	struct TreeNode *root = p;
+
+	populate_directory_sizes(root);
+
+	int result = 0;
+	Vec *stack = vec_malloc(10);
+	vec_push(stack, root);
+	while (stack->count > 0) {
+		struct TreeNode *node = vec_pop(stack);
+		if (node->size <= 100000 && node->children_count > 0) {
+			result += node->size;
+		}
+		for (int i = 0; i < node->children_count; i++) {
+			vec_push(stack, node->children[i]);
+		}
+	}
+
+	printf("%d\n", result);
+}
+
+static void day7_part2(void *p)
+{
+	struct TreeNode *root = p;
+
+	populate_directory_sizes(root);
+
+	int needed_space = UPDATE_SIZE - (TOTAL_FS_SIZE - root->size);
+
+	int result = INT_MAX;
+	Vec *stack = vec_malloc(10);
+	vec_push(stack, root);
+	while (stack->count > 0) {
+		struct TreeNode *node = vec_pop(stack);
+		if (node->size >= needed_space && node->children_count > 0) {
+			result = MIN(result, node->size);
+		}
+		for (int i = 0; i < node->children_count; i++) {
+			vec_push(stack, node->children[i]);
+		}
+	}
+
+	printf("%d\n", result);
+}
+
+ADD_SOLUTION(7, day7_parse, day7_part1, day7_part2);

main.c

@@ -14,6 +14,7 @@
 #include "day4.c"
 #include "day5.c"
 #include "day6.c"
+#include "day7.c"
 
 Solution *find_solution(int day)
 {

vec.h

@@ -23,17 +23,18 @@ static inline void vec_push(Vec *vec, void* value)
 {
 	if (vec->count >= vec->capacity) {
 		vec->capacity = (vec->capacity + 1) * 2;
-		vec->data = (void**)realloc(vec->data, vec->capacity);
+		vec->data = (void**)realloc(vec->data, vec->capacity * sizeof(void*));
 	}
 	vec->data[vec->count++] = value;
 }
 
-inline void vec_pop(Vec* vec)
+static inline void *vec_pop(Vec* vec)
 {
 	vec->count--;
+	return vec->data[vec->count];
 }
 
-inline void vec_free(Vec *v)
+static inline void vec_free(Vec *v)
 {
 	free(v->data);
 	free(v);