Day 6 solutions

.gitignore

@@ -5,3 +5,4 @@
 *.out
 *.swp
 .vscode/
+.gdb_history

6/6-1.c

@@ -0,0 +1,90 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "../check_alloc.h"
+
+#define CYCLE 6
+#define STARTING_TIMER 8
+unsigned int INITIAL_CONDITION[] = {3, 4, 3, 1, 2};
+
+// LIST DATASTRUCTURE
+#define INITIAL_SIZE 20
+
+typedef struct
+{
+    unsigned int *list;
+    size_t size;
+    size_t capacity;
+} LIST;
+
+void free_list(LIST *list)
+{
+    free(list->list);
+    free(list);
+}
+
+LIST *new_list(void)
+{
+    LIST *p_list = calloc(1, sizeof(LIST));
+    p_list->capacity = INITIAL_SIZE;
+    p_list->list = calloc(p_list->capacity, sizeof(unsigned int));
+    return p_list;
+}
+
+void add_list(LIST *list, unsigned int elem)
+{
+    if (list->size >= list->capacity)
+    {
+        list->capacity *= 2;
+        list->list = realloc(list->list, list->capacity * sizeof(unsigned int));
+        CHECK_ALLOC(list->list);
+    }
+    list->list[list->size] = elem;
+    list->size++;
+}
+
+void print_list(LIST *list)
+{
+    for (size_t i = 0; i < list->size; i++)
+    {
+        printf("%d ", list->list[i]);
+    }
+    putchar('\n');
+}
+
+//
+
+void step_time(LIST *state)
+{
+    size_t size_before = state->size;
+    for (size_t i = 0; i < size_before; i++)
+    {
+        if (state->list[i] == 0)
+        {
+            state->list[i] = CYCLE;
+            add_list(state, STARTING_TIMER);
+        }
+        else
+        {
+            state->list[i]--;
+        }
+    }
+}
+
+int main(int argc, char const *argv[])
+{
+    LIST *state = new_list();
+    size_t ic_size = sizeof(INITIAL_CONDITION) / sizeof(INITIAL_CONDITION[0]);
+    for (size_t i = 0; i < ic_size; i++)
+    {
+        add_list(state, INITIAL_CONDITION[i]);
+    }
+    for (size_t i = 0; i < 80; i++)
+    {
+        step_time(state);
+        printf("%lu\t", i);
+        fflush(stdout);
+        // print_list(state);
+    }
+    printf("\n%lu\n", state->size);
+    return 0;
+}

6/6-2.c

@@ -0,0 +1,48 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+// IC
+#define TIMESPAN_DAYS 256
+unsigned long INITIAL_CONDITION[] = {3, 4, 3, 1, 2};
+
+int main(int argc, char const *argv[])
+{
+    // IC LOGIC
+    bool is_ic_done = false;
+    size_t ic_done_count = 0;
+    size_t ic_size = sizeof(INITIAL_CONDITION) / sizeof(INITIAL_CONDITION[0]);
+
+    // Had to scratch this one out on paper to figure it out.
+    unsigned long cycles7[7] = {0};
+    unsigned long cycles9[9] = {0};
+    unsigned long total = 0;
+
+    for (size_t t = 0; t < TIMESPAN_DAYS; t++)
+    {
+        // APPLY IC BY ADDING TO CYCLES AT OFFSETS SPECIFIED IN ICS
+        if (!is_ic_done)
+        {
+            for (size_t i = 0; i < ic_size; i++)
+            {
+                if (t == INITIAL_CONDITION[i])
+                {
+                    cycles9[t % 9]++;
+                    total++;
+                    ic_done_count++;
+                }
+            }
+            if (ic_done_count > ic_size)
+                is_ic_done = true;
+        }
+
+        // UPDATE POPULATION
+        unsigned long v = cycles7[t % 7];
+        total += cycles9[t % 9];
+        total += v;
+        cycles7[t % 7] += cycles9[t % 9];
+        cycles9[t % 9] += v;
+    }
+    printf("%lu\n", total);
+    return 0;
+}

6/6-2ridiculous_threads.c

@@ -0,0 +1,111 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "../check_alloc.h"
+#include <pthread.h>
+
+// EXTENDING THE DUMB SOLUTION WITH THREADS - STILL BAD BECAUSE OF THE ALGORITHM'S BAD TIME COMPLEXITY.
+
+#define CYCLE 6
+#define STARTING_TIMER 8
+unsigned int INITIAL_CONDITION[] = {3, 4, 3, 1, 2};
+
+// LIST DATASTRUCTURE
+#define INITIAL_SIZE 20
+
+typedef struct
+{
+    unsigned int *list;
+    size_t size;
+    size_t capacity;
+} LIST;
+
+void free_list(LIST *list)
+{
+    free(list->list);
+    free(list);
+}
+
+LIST *new_list(void)
+{
+    LIST *p_list = calloc(1, sizeof(LIST));
+    p_list->capacity = INITIAL_SIZE;
+    p_list->list = calloc(p_list->capacity, sizeof(unsigned int));
+    return p_list;
+}
+
+void add_list(LIST *list, unsigned int elem)
+{
+    if (list->size >= list->capacity)
+    {
+        list->capacity *= 2;
+        list->list = realloc(list->list, list->capacity * sizeof(unsigned int));
+        CHECK_ALLOC(list->list);
+    }
+    list->list[list->size] = elem;
+    list->size++;
+}
+
+void print_list(LIST *list)
+{
+    for (size_t i = 0; i < list->size; i++)
+    {
+        printf("%d ", list->list[i]);
+    }
+    putchar('\n');
+}
+
+//
+
+void step_time(LIST *state)
+{
+    size_t size_before = state->size;
+    for (size_t i = 0; i < size_before; i++)
+    {
+        if (state->list[i] == 0)
+        {
+            state->list[i] = CYCLE;
+            add_list(state, STARTING_TIMER);
+        }
+        else
+        {
+            state->list[i]--;
+        }
+    }
+}
+
+void *manage_part(void *args)
+{
+    LIST *state = (LIST *)args;
+    for (size_t i = 0; i < 256; i++)
+    {
+        step_time(state);
+        printf("%lu\t", i);
+        fflush(stdout);
+        // print_list(state);
+    }
+}
+
+int main(int argc, char const *argv[])
+{
+    size_t ic_size = sizeof(INITIAL_CONDITION) / sizeof(INITIAL_CONDITION[0]);
+    LIST *parts[ic_size];
+    pthread_t threads[ic_size];
+
+    // MAKE THREADS AND STATE PARTS
+    for (size_t i = 0; i < ic_size; i++)
+    {
+        parts[i] = new_list();
+        add_list(parts[i], INITIAL_CONDITION[i]);
+        pthread_create(&threads[i], NULL, manage_part, parts[i]);
+    }
+
+    size_t total = 0;
+    for (size_t i = 0; i < ic_size; i++)
+    {
+        pthread_join(threads[i], NULL);
+        total += parts[i]->size;
+    }
+
+    printf("\n%lu\n", total);
+    return 0;
+}