Day2 C

day2/c/day2.c

@@ -0,0 +1,75 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define LINE_MAX_LENGTH 256
+
+#define RED_CUBES 12
+#define GREEN_CUBES 13
+#define BLUE_CUBES 14
+#define max(a, b) (a > b ? a : b)
+
+int main() {
+    char *p, *buf, c;
+    int sum = 0, id = 0, count = 0;
+    unsigned int part2_sum = 0;
+
+    buf = (char *)malloc(LINE_MAX_LENGTH);
+    memset(buf, 0, LINE_MAX_LENGTH);
+    p = buf;
+
+    while ((c = getchar()) != EOF) {
+        *p++ = c;
+        if (c == '\n') {
+            int possible = 1;
+            int r = 0, g = 0, b = 0;
+            p = buf;
+            // Read Game ID
+            sscanf(p, "Game %i", &id);
+            // Move to char ':'
+            while (*p++ != ':');
+
+            // Read draws
+            for (;;) {
+                sscanf(p, "%i %c", &count, &c);
+
+                if ((c == 'r' && count > RED_CUBES) || (c == 'g' && count > GREEN_CUBES) || (c == 'b' && count > BLUE_CUBES)) {
+                    possible = 0;
+                }
+
+                switch (c) {
+                    case 'r':
+                        r = max(r, count);
+                        break;
+                    case 'g':
+                        g = max(g, count);
+                        break;
+                    case 'b':
+                        b = max(b, count);
+                        break;
+                }
+                // Read to next separator or end of line
+                while (*p != '\n' && *p != ',' && *p != ';') p++;
+
+                if (*p == '\n') {
+                    break;
+                }
+
+                p+=2;
+            }
+
+            if (possible) {
+                sum += id;
+            }
+
+            part2_sum += r * g * b;
+
+            memset(buf, 0, LINE_MAX_LENGTH);
+            p = buf;
+        }
+    }
+
+    free(buf);
+    printf("%i\n", sum);
+    printf("%u\n", part2_sum);
+}