2022: Day 1 complete

2022/1.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int comp(const void *a, const void *b) {
+  int n = *(int *)a;
+  int m = *(int *)b;
+  return n - m;
+}
+
+int main(int argc, char *argv[]) {
+
+  if (argc != 2) {
+    fprintf(stderr, "USAGE: %s input_file\n", argv[0]);
+    return 1;
+  }
+
+  FILE *fd = fopen(argv[1], "r");
+  if (!fd) {
+    fprintf(stderr, "Error opening file\n");
+    return 1;
+  }
+
+  char line[50] = {0};
+  int idx = 0, elves[1000] = {0};
+
+  while (fgets(line, sizeof line / sizeof *line, fd) != NULL) {
+    if (strlen(line) == 1) {
+      idx++;
+    } else {
+      elves[idx] += atoi(line);
+    }
+  }
+
+  qsort(elves, idx, sizeof(int), comp);
+
+  printf("Elf with the most calories:     %d\n", elves[idx - 1]);
+  printf("Elf with the 2nd most calories: %d\n", elves[idx - 2]);
+  printf("Elf with the 3rd most calories: %d\n", elves[idx - 3]);
+  printf("Total:                          %d\n",
+         elves[idx - 1] + elves[idx - 2] + elves[idx - 3]);
+
+  fclose(fd);
+  return 0;
+}