diff --git a/2021/day25/Makefile b/2021/day25/Makefile
index 08142b9..b420a74 100644
--- a/2021/day25/Makefile
+++ b/2021/day25/Makefile
@@ -45,7 +45,7 @@ export PATH := .:$(PATH)
 
 .PHONY: clean all compile assembly memcheck memcheck1 memcheck2 ex1 ex2
 
-all: ex1
+all: ex1 ex2
 
 memcheck: memcheck1
 
@@ -62,8 +62,8 @@ assembly: aoc-c.s
 ex1: aoc-c
 	@$(TIME) aoc-c -p 1 < $(INPUT)
 
-ex2: aoc-c
-	@$(TIME) aoc-c -p 2 < $(INPUT)
+ex2: day_25a
+	@$(TIME) day_25a $(INPUT)
 
 clean:
 	@rm -f aoc-c core* vgcore* gmon.out aoc-c.s
diff --git a/2021/day25/aoc-c.c b/2021/day25/aoc-c.c
index b002888..e4b4789 100644
--- a/2021/day25/aoc-c.c
+++ b/2021/day25/aoc-c.c
@@ -141,7 +141,7 @@ static struct map *read_input()
     ssize_t buflen;
     struct map *map;
 
-    /*  use calloc() to  ensure cur & next are set to  NULL */
+    /*  use calloc() to ensure cur & next are set to NULL */
     if (!(map = calloc(1, sizeof(struct map))))
         goto end;
 
@@ -151,7 +151,7 @@ static struct map *read_input()
     if (!(map->next = strdup(map->cur)))
         goto freemem;
     map->ncols = strchr(map->cur, '\n') - map->cur;
-    /* next line works  if there is nothing after the last input data last line,
+    /* next line works if there is nothing after the last input data last line,
      * i.e. if last char of input (at position bufflen - 1) is the '\n' on the
      * last valid puzzle line.
      */