From 74a3cc2f48dc7d6cfd27634b3468e0476c9d7caa Mon Sep 17 00:00:00 2001
From: Peter <peterr.00000@gmail.com>
Date: Fri, 10 Dec 2021 17:52:34 +0800
Subject: [PATCH] Day 10 solutions

---
 10/10-1.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 182 insertions(+)
 create mode 100644 10/10-1.c

diff --git a/10/10-1.c b/10/10-1.c
new file mode 100644
index 0000000..fca091a
--- /dev/null
+++ b/10/10-1.c
@@ -0,0 +1,182 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "../check_alloc.h"
+
+// Fun fact: I got really lucky on this one - for some reason my sorting wasn't
+// working, but I guessed middle+1th index and got the right answer on my laptop
+// In the end the issue is that I didn't use LIST_TYPE in the LINE_RESULT struct
+
+#define OPENING_BRACKETS "([{<"
+
+// LIST DATASTRUCTURE
+
+#define INITIAL_SIZE 20
+typedef size_t LIST_TYPE;
+
+typedef struct
+{
+    LIST_TYPE *list;
+    size_t size;
+    size_t capacity;
+} LIST;
+
+LIST *new_list(void)
+{
+    LIST *p_list = calloc(1, sizeof(LIST));
+    CHECK_ALLOC(p_list);
+    p_list->capacity = INITIAL_SIZE;
+    p_list->list = calloc(p_list->capacity, sizeof(LIST_TYPE));
+    CHECK_ALLOC(p_list->list);
+    p_list->size = 0;
+    return p_list;
+}
+
+void add_list(LIST *list, LIST_TYPE elem)
+{
+    if (list->size >= list->capacity)
+    {
+        list->capacity *= 2;
+        list->list = realloc(list->list, list->capacity * sizeof(LIST_TYPE));
+        CHECK_ALLOC(list->list);
+    }
+    list->list[list->size] = elem;
+    list->size++;
+}
+
+//
+
+unsigned int get_error_points(char c)
+{
+    switch (c)
+    {
+    case ')':
+        return 3;
+    case ']':
+        return 57;
+    case '}':
+        return 1197;
+    case '>':
+        return 25137;
+    }
+    return 0;
+}
+
+unsigned int get_autocomplete_points(char c)
+{
+    switch (c)
+    {
+    case ')':
+        return 1;
+    case ']':
+        return 2;
+    case '}':
+        return 3;
+    case '>':
+        return 4;
+    }
+    return 0;
+}
+
+char closing_char(char opening_char)
+{
+    switch (opening_char)
+    {
+    case '(':
+        return ')';
+    case '[':
+    case '{':
+    case '<':
+        return opening_char + 2;
+    }
+    return '\0';
+}
+
+enum MODE
+{
+    ERROR,
+    AUTOCOMPLETE
+};
+
+typedef struct
+{
+    enum MODE mode;
+    LIST_TYPE points;
+} LINE_RESULT;
+
+LINE_RESULT process_line(char *line)
+{
+    LINE_RESULT result;
+    size_t len = strlen(line);
+
+    // BRACKET STACK
+    size_t stack_pointer = 0;
+    char stack[len];
+
+    for (size_t i = 0; i < len; i++)
+    {
+        if (line[i] == '\n')
+            break;
+        if (strchr(OPENING_BRACKETS, line[i]) != NULL)
+        {
+            stack[stack_pointer] = line[i];
+            stack_pointer++;
+        }
+        else if (closing_char(stack[stack_pointer - 1]) == line[i])
+        {
+            stack_pointer--;
+        }
+        else
+        {
+            // printf("%s - Expected %c, but found %c instead\n",line,closing_char(stack[stack_pointer-1]),line[i]);
+            result.mode = ERROR;
+            result.points = get_error_points(line[i]);
+            return result;
+        }
+    }
+
+    // LINE IS INCOMPLETE
+    result.mode = AUTOCOMPLETE;
+    result.points = 0;
+    while (stack_pointer > 0)
+    {
+        result.points *= 5;
+        result.points += get_autocomplete_points(closing_char(stack[stack_pointer - 1]));
+        stack_pointer--;
+    }
+
+    return result;
+}
+
+void read_file(char *file, unsigned int *err_points, LIST *autocomplete_points)
+{
+    FILE *p_file = fopen(file, "r");
+    CHECK_ALLOC(p_file);
+    char buf[BUFSIZ];
+    int i = 0;
+    while (fgets(buf, sizeof buf, p_file) != NULL)
+    {
+        LINE_RESULT line = process_line(buf);
+        if (line.mode == ERROR)
+            *err_points += line.points;
+        else // AUTOCOMPLETE
+            add_list(autocomplete_points, line.points);
+    }
+}
+
+int compare_list(const void *a, const void *b)
+{
+    if (*(LIST_TYPE *)a == *(LIST_TYPE *)b)
+        return 0;
+    return *(LIST_TYPE *)a > *(LIST_TYPE *)b ? 1 : -1;
+}
+
+int main(int argc, char const *argv[])
+{
+    LIST *p_autocomplete_list = new_list();
+    unsigned int err_points = 0;
+    read_file("input", &err_points, p_autocomplete_list);
+    qsort(p_autocomplete_list->list, p_autocomplete_list->size, sizeof(p_autocomplete_list->list[0]), compare_list);
+    printf("ERROR POINTS %u, AUTOCOMPLETE POINTS %zu\n", err_points, p_autocomplete_list->list[p_autocomplete_list->size / 2]);
+    return 0;
+}