diff --git a/day1/Makefile b/day1/Makefile
index 39f2ae3..42f564d 100644
--- a/day1/Makefile
+++ b/day1/Makefile
@@ -15,7 +15,7 @@ INPUT_DEST=src/input.c
 COMMON_FLAGS+= -W -Wall -fno-strict-aliasing $(addprefix -I,$(INCLUDE))
 
 COMMON_FLAGS+=-msse -msse2 -msse3
-COMMON_FLAGS+=-D_PART1
+COMMON_FLAGS+=-D_PART1 -D_PART2
 
 OPT_FLAGS?= -march=native -fgraphite -fopenmp -floop-parallelize-all -ftree-parallelize-loops=4 \
 	    -floop-interchange -ftree-loop-distribution -floop-strip-mine -floop-block \
diff --git a/day1/include/input.h b/day1/include/input.h
index 7d203f7..938b75c 100644
--- a/day1/include/input.h
+++ b/day1/include/input.h
@@ -13,11 +13,6 @@ typedef uint16_t input_t;
 extern const size_t  INPUT_SIZE;
 extern const input_t INPUT[];
 
-struct ipair {
-	input_t prev;
-	input_t next;
-};
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/day1/include/pairs.h b/day1/include/pairs.h
new file mode 100644
index 0000000..6ca3df4
--- /dev/null
+++ b/day1/include/pairs.h
@@ -0,0 +1,24 @@
+#ifndef _PAIRS_H
+#define _PAIRS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <input.h>
+
+struct ipair {
+	input_t prev;
+	input_t next;
+};
+
+#ifdef __cplusplus
+uint64_t chk_pair(const ipair* __restrict__ pair) __attribute__((pure));
+uint64_t sum_pairs(uint64_t length, const input_t input[const __restrict__ length]) __attribute__((pure));
+}
+#else
+uint64_t chk_pair(const struct ipair* restrict pair) __attribute__((pure));
+uint64_t sum_pairs(uint64_t length, const input_t input[const restrict length]) __attribute__((pure));
+#endif
+
+#endif /* _PAIRS_H */
diff --git a/day1/src/p1.c b/day1/src/p1.c
index 0914b19..284761f 100644
--- a/day1/src/p1.c
+++ b/day1/src/p1.c
@@ -1,18 +1,27 @@
+
 #include <input.h>
 
+#include <pairs.h>
+
 __attribute__((pure))
 uint64_t chk_pair(const struct ipair* restrict pair)
 {
 	return pair->prev < pair->next;
 }
 
-int part1(uint64_t* restrict _res)
+__attribute__((pure))
+uint64_t sum_pairs(uint64_t length, const input_t input[const restrict length])
 {
 	uint64_t res = 0;
-	for(size_t i=0;i<INPUT_SIZE-1;i++)
+	for(size_t i=0;i<length-1;i++)
 	{
-		res += chk_pair((const struct ipair*)(INPUT+i));
+		res += chk_pair((const struct ipair*)(input+i));
 	}
-	*_res = res;
+	return res;
+}
+
+int part1(uint64_t* restrict _res)
+{
+	*_res = sum_pairs(INPUT_SIZE, INPUT);
 	return 0;
 }
diff --git a/day1/src/p2.c b/day1/src/p2.c
index 1e850f8..73b7e08 100644
--- a/day1/src/p2.c
+++ b/day1/src/p2.c
@@ -1,11 +1,30 @@
 #include <input.h>
 
-#include <tracem/macros.h>
+#include <pairs.h>
+
+struct window {
+	input_t pre, cur, suc;
+};
+
+__attribute__((pure))
+inline static input_t sum_window(const struct window* restrict w)
+{
+	return w->pre + w->cur + w->suc;
+}
 
 int part2(uint64_t* restrict _res)
 {
 	uint64_t res=0;
-	TODO("unimplemented");
+
+	for(size_t i=0;i<INPUT_SIZE-2;i++)
+	{
+		struct ipair w6;
+		w6.prev = sum_window((const struct window*)(INPUT+i));
+		w6.next = sum_window((const struct window*)(INPUT+i+1));
+		
+		res += (w6.prev < w6.next);
+	}
+
 	*_res = res;
 	return 0;
 }