Solve 2015 days 11-14.

2015/d11.py

@@ -0,0 +1,49 @@
+data = open(0).read().strip()
+
+def is_valid(pw):
+    # Passwords must include one increasing straight of at least three letters,
+    # like abc, bcd, cde, and so on, up to xyz. They cannot skip letters; abd
+    # doesn't count.
+    ords = list(map(ord, pw))
+    for i in range(len(ords) - 2):
+        if ords[i] + 1 == ords[i + 1] and ords[i + 1] + 1 == ords[i + 2]:
+            break
+    else:
+        return False
+
+    # Passwords may not contain the letters i, o, or l, as these letters can be
+    # mistaken for other characters and are therefore confusing.
+    for c in "iol":
+        if c in pw:
+            return False
+
+    # Passwords must contain at least two different, non-overlapping pairs of letters, like aa, bb, or zz
+    pairs = set()
+    for i in range(len(pw) - 1):
+        if pw[i] == pw[i + 1]:
+            pairs.add(pw[i])
+    if not len(pairs) >= 2:
+        return False
+    return True
+
+def inc(pw):
+    pw = list(map(ord, pw))
+    for i in range(len(pw) - 1, -1, -1):
+        pw[i] += 1
+        if pw[i] == ord('z') + 1:
+            pw[i] = ord('a')
+        else:
+            break
+    return "".join(map(chr, pw))
+
+part_1 = False
+valid_count = 0
+while True:
+    data = inc(data)
+    if is_valid(data):
+        valid_count += 1
+    if part_1 and valid_count == 1:
+        break
+    elif valid_count == 2:
+        break
+print(data)