diff --git a/d04/run.c b/d04/run.c
new file mode 100644
index 0000000..ab185f6
--- /dev/null
+++ b/d04/run.c
@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <openssl/md5.h>
+
+/**
+ compile with `tcc -lssl run.c`
+ run with `./a.out | grep -F ' 000000'`, then CTRL+C
+ */
+void main(int argc, char **argv) {
+	unsigned char digest[16];
+	char string[32];
+	MD5_CTX context;
+  for (int i=1;;i++) {
+		printf("%d ",i);
+		sprintf(string,"ckczppom%d",i);
+		MD5_Init(&context);
+		MD5_Update(&context, string, strlen(string));
+		MD5_Final(digest, &context);
+		for(int i = 0; i < 16; ++i) {
+	    printf("%02x", (unsigned int)digest[i]);
+		}
+		printf("\n");
+	}
+}
diff --git a/d05/run.py b/d05/run.py
new file mode 100644
index 0000000..f508fde
--- /dev/null
+++ b/d05/run.py
@@ -0,0 +1,17 @@
+import sys
+
+def isnice1(l):
+    if any(a+b in ['ab','cd','pq','xy'] for (a,b) in zip(l,l[1:])):
+        return False
+    vowels = sum(c in 'aeiou' for c in l)
+    inarow = any(a==b for (a,b) in zip(l,l[1:]))
+    return vowels > 2 and inarow 
+
+def isnice2(l):
+    xyxy = any(l[i:i+2] == l[j:j+2] for i in range(len(l)-1) for j in range(i+2,len(l)-1))
+    gfg = any(a == b for a,b in zip(l[0:],l[2:]))
+    return xyxy and gfg
+
+isnice = isnice2 if sys.argv[1] == "2" else isnice1
+
+print(sum(isnice(l[:-1]) for l in sys.stdin.readlines()))
diff --git a/d06/part1.py b/d06/part1.py
new file mode 100644
index 0000000..291b262
--- /dev/null
+++ b/d06/part1.py
@@ -0,0 +1,18 @@
+import sys
+
+M = [[False for _ in range(1000)] for _ in range(1000)]
+
+for l in sys.stdin.readlines():
+    I = l[:-1].split(' ')
+    xf,yf = list(map(int,I[-3].split(',')))
+    xt,yt = list(map(int,I[-1].split(',')))
+    for x in range(xf,xt+1):
+        for y in range(yf,yt+1):
+            if I[-4] == 'on':
+                M[x][y] = True
+            elif I[-4] == 'off':
+                M[x][y] = False
+            else:
+                M[x][y] = not M[x][y]
+
+print(sum(x for C in M for x in C))
diff --git a/d06/part2.py b/d06/part2.py
new file mode 100644
index 0000000..003b0f4
--- /dev/null
+++ b/d06/part2.py
@@ -0,0 +1,18 @@
+import sys
+
+M = [[0 for _ in range(1000)] for _ in range(1000)]
+
+for l in sys.stdin.readlines():
+    I = l[:-1].split(' ')
+    xf,yf = list(map(int,I[-3].split(',')))
+    xt,yt = list(map(int,I[-1].split(',')))
+    for x in range(xf,xt+1):
+        for y in range(yf,yt+1):
+            if I[-4] == 'on':
+                M[x][y] += 1
+            elif I[-4] == 'off':
+                M[x][y] = max(0, M[x][y]-1)
+            else:
+                M[x][y] += 2
+
+print(sum(x for C in M for x in C))