Solve 2016 days 4 and 5.

2016/d4.py

@@ -0,0 +1,44 @@
+from lib import *
+
+second = True
+data = open(0).read()
+
+
+def decipher(cipher, shift):
+    clear = ""
+    for c in cipher:
+        if c == "-":
+            nc = "-"
+        else:
+            nc = LETTERS_LOWER[(LETTERS_LOWER.index(c) + shift) % len(LETTERS_LOWER)]
+        clear += nc
+    return clear
+
+
+if not second:
+    s = 0
+    for line in data.splitlines():
+        hash, key = line.split("[")
+        key = key.replace("]", "")
+
+        counts = {}
+        for c in LETTERS_LOWER:
+            counts[c] = hash.count(c)
+
+        counts = sorted(list(zip(counts.values(), counts.keys())), key=lambda t: (t[0], -ord(t[1])), reverse=True)
+
+        real = True
+        for i, (_, c) in enumerate(counts[:5]):
+            if c != key[i]:
+                real = False
+        if real:
+            s += int(hash.split("-")[-1])
+    print(s)
+else:
+    for line in data.splitlines():
+        line = line[:-7]
+        hash = "-".join(line.split("-")[:-1])
+        shift = int(line.split("-")[-1])
+        cleartext = decipher(hash, shift)
+        if "north" in cleartext and "pole" in cleartext:
+            print(shift)

2016/d5.py

@@ -0,0 +1,30 @@
+from lib import *
+import hashlib
+
+second = True
+data = open(0).read().strip()
+
+if second:
+    p = [" " for _ in range(8)]
+    for i in range(10**12):
+        s = data + str(i)
+        h = hashlib.md5(s.encode()).hexdigest()
+        if h.startswith("0" * 5) and h[5] in "01234567":
+            index = int(h[5])
+            if p[index] == " ":
+                p[index] = h[6]
+                # print("\r" + "".join(p))
+        if not " " in p:
+            p = "".join(p)
+            break
+else:
+    p = ""
+    for i in range(10**12):
+        s = data + str(i)
+        h = hashlib.md5(s.encode()).hexdigest()
+        if h.startswith("0" * 5):
+            p += h[5]
+        if len(p) == 8:
+            break
+
+print(p)