Day 19 solutions

19/19-1and2.c

@@ -0,0 +1,128 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include "../check_alloc.h"
+
+#define LUT_LENGTH 512
+#define ITERATIONS 50
+// THERE'S SOME UNDEFINED BEHAVIOR WHICH
+// EXPANDS FROM THE CORNERS - EXCLUDE THESE AREAS
+#define EXCLUDED_AREA (ITERATIONS + 1)
+#define EXPANDED_SPACE (ITERATIONS + EXCLUDED_AREA)
+
+bool *get_lut(FILE *p_file)
+{
+    char buf[BUFSIZ];
+    bool *lut = calloc(LUT_LENGTH, sizeof(bool));
+    fgets(buf, sizeof buf, p_file);
+    for (size_t i = 0; i < LUT_LENGTH; i++)
+        lut[i] = buf[i] == '#';
+    return lut;
+}
+
+typedef struct
+{
+    bool **space;
+    int space_size;
+} SPACE;
+
+SPACE *get_space(FILE *p_file)
+{
+    SPACE *p_space = malloc(sizeof(SPACE));
+    CHECK_ALLOC(p_space);
+    char buf[BUFSIZ];
+    fgets(buf, sizeof buf, p_file);
+    if (strlen(buf) >= BUFSIZ)
+        exit(EXIT_FAILURE);
+    size_t ic_size = strlen(buf) - 1; // -1 FOR \n
+    p_space->space_size = ic_size + 2 * (EXPANDED_SPACE);
+
+    // ALLOCATE SPACE
+    p_space->space = calloc(p_space->space_size, sizeof(bool *));
+    CHECK_ALLOC(p_space->space);
+    for (size_t i = 0; i < p_space->space_size; i++)
+    {
+        p_space->space[i] = calloc(p_space->space_size, sizeof(bool));
+        CHECK_ALLOC(p_space->space[i]);
+    }
+    // SPACE
+
+    for (size_t j = 0; j < ic_size; j++)
+    {
+        for (size_t i = 0; i < ic_size; i++)
+            p_space->space[j + EXPANDED_SPACE][i + EXPANDED_SPACE] = buf[i] == '#';
+        fgets(buf, sizeof buf, p_file);
+    }
+    return p_space;
+}
+
+void print_space(SPACE *space)
+{
+    for (size_t i = 0; i < space->space_size; i++)
+    {
+        for (size_t j = 0; j < space->space_size; j++)
+            putchar(space->space[i][j] ? '#' : '.');
+        putchar('\n');
+    }
+    putchar('\n');
+}
+
+bool space_value(SPACE *space, int i, int j)
+{
+    if (i < 0 || j < 0 || i >= space->space_size || j >= space->space_size)
+        return false;
+    return space->space[i][j];
+}
+
+//
+void step_space(SPACE *space, bool *lut)
+{
+    bool buffer[space->space_size][space->space_size];
+    memset(buffer, false, space->space_size * space->space_size * sizeof(bool));
+    for (int i = 0; i < space->space_size; i++)
+    {
+        for (int j = 0; j < space->space_size; j++)
+        {
+            char number[9];
+            int idx = 0;
+            for (int y = j - 1; y <= j + 1; y++)
+            {
+                for (int x = i - 1; x <= i + 1; x++)
+                {
+                    number[idx] = space_value(space, y, x) ? '1' : '0';
+                    idx++;
+                }
+            }
+            buffer[j][i] = lut[strtol(number, NULL, 2)];
+        }
+    }
+    for (int i = 0; i < space->space_size; i++)
+        memcpy(space->space[i], buffer[i], space->space_size * sizeof(bool));
+}
+
+int count_space(SPACE *space)
+{
+    int count = 0;
+    // IGNORE BOUNDARY (REPRESENTS INFINITE SIZE OF SPACE)
+    for (size_t i = EXCLUDED_AREA; i < space->space_size - EXCLUDED_AREA; i++)
+        for (size_t j = EXCLUDED_AREA; j < space->space_size - EXCLUDED_AREA; j++)
+            count += space->space[i][j];
+    return count;
+}
+
+int main(int argc, char const *argv[])
+{
+    FILE *p_file = fopen("input", "r");
+    bool *lut = get_lut(p_file);
+
+    fscanf(p_file, "%s", NULL); // SKIP LINE
+
+    SPACE *space = get_space(p_file);
+
+    for (size_t i = 0; i < ITERATIONS; i++)
+        step_space(space, lut);
+    printf("COUNT %d\n", count_space(space));
+
+    return 0;
+}