c 2022 3 part 1

c/2022/3/problem.c

@@ -0,0 +1,78 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../../lib/aoc.h"
+
+typedef struct Compartment {
+  char contents[52];
+} Compartment;
+
+void print_compartment(Compartment *c) {
+  for (char i = 'a'; i <= 'z'; i++) {
+    printf("%c", i);
+  }
+  for (char i = 'A'; i <= 'Z'; i++) {
+    printf("%c", i);
+  }
+  printf("\n");
+  for (char i = 0; i < 52; i++) {
+    printf("%d", c->contents[i]);
+  }
+  printf("\n\n");
+}
+
+Compartment fill_compartment(const char *half) {
+  Compartment compartment;
+  for (char i = 0; i < 52; i++) {
+    compartment.contents[i] = 0;
+  }
+
+  for (int i = 0; i < strlen(half); i++) {
+    char c = half[i];
+    if (c >= 'a' && c <= 'z') {
+      compartment.contents[c - 'a'] = 1;
+    } else {
+      compartment.contents[c - 'A' + 26] = 1;
+    }
+  }
+  fflush(stdout);
+  return compartment;
+}
+
+int priority(char *line) {
+  int len = strlen(line);
+  char *second = malloc((len / 2) + 1);
+  strcpy(second, line + (len / 2));
+  line[len / 2] = '\0';
+
+  Compartment c1 = fill_compartment(line);
+  Compartment c2 = fill_compartment(second);
+
+  // print_compartment(&c1);
+  // print_compartment(&c2);
+
+  for (int i = 0; i < 52; i++) {
+    if (c1.contents[i] && c2.contents[i]) {
+      free(second);
+      return i + 1;
+    }
+  }
+
+  free(second);
+  return 0;
+}
+
+int main() {
+  char *line;
+
+  int sum = 0;
+  while ((line = aoc_read_line()) != NULL) {
+    sum += priority(line);
+  }
+
+  printf("Part 1: %d\n", sum);
+
+  aoc_free();
+  return 0;
+}