reduce complexity + just free() in a single place

- therefor if the program gets extended, its unlikly that
  someone will forget to call free()
- also this gets rid of copy-paste free() calls (which look stupid)

challenge/challenge.c

@@ -3,30 +3,24 @@
 #include <stdlib.h>
 
 int main() {
-    int bytes_read;
+    int ret;
     size_t nbytes = 0;
     char *my_string = NULL;
     char *password = "23door42\n";
 
     puts("Please enter Password: ");
+    ret = getline(&my_string, &nbytes, stdin);
 
-    bytes_read = getline(&my_string, &nbytes, stdin);
-
-    if(bytes_read == -1) {
+    if (ret == -1) {
         puts("Error");
-        free(my_string);
-        return -1;
-    } else {
-        if (strcmp(my_string, password) == 0) {
+    } else if (strcmp(my_string, password) == 0) {
         puts("Success");
-            free(my_string);
-            return 0;
+        ret = 0;
     } else {
         puts("How about no?!");
-            free(my_string);
-            return -1;
-        }
+        ret = -1;
     }
 
-    return 0;
+    free(my_string);
+    return ret;
 }