day 6

d06/part1.py

@@ -0,0 +1,8 @@
+import sys
+
+L = sys.stdin.read()
+
+for (i, (a,b,c,d)) in enumerate(zip(L,L[1:],L[2:],L[3:])):
+	if not (b == a or c == a or c == b or d == a or d == b or d == c):
+		print(i+4, L[i:i+4])
+		break

d06/part2.py

@@ -0,0 +1,23 @@
+import sys
+
+def window_iter(it, size):
+	from itertools import tee
+	wt = tee(it, size)  # tuple(n iterables)
+	# shift each iterator by its place in the window
+	for (i,x) in enumerate(wt):
+		for _ in range(i):
+			next(x)
+	while True:
+		try:
+			yield tuple(next(x) for x in wt)
+		except RuntimeError:  # RuntimeError: generator raised StopIteration
+			break
+
+L = sys.stdin.read()
+
+from itertools import combinations as comb
+
+for (i, T) in enumerate(window_iter(L,14)):
+	if all(map(lambda x: x[0] != x[1], comb(T,2))):
+		print(i+14, L[i:i+14])
+		break

d06/part2b.py

@@ -0,0 +1,13 @@
+import sys
+from collections import deque
+
+dq = deque()
+for (i,c) in enumerate(sys.stdin.read()):
+	equals = list(filter(lambda x: c == x[1], enumerate(dq)))
+	if len(equals)>0: # remove left part until a char equal to c, included
+		for _ in range(equals[-1][0]+1):
+			dq.popleft()
+	if len(dq) == 13: # if we have 13+1 distinct chars, we're good
+		print(i+1)
+		break
+	dq.append(c)

d06/part2c.py

@@ -0,0 +1,6 @@
+import sys
+s = sys.stdin.read()
+for i in range(14, len(s)):
+	if len(set(s[i-14:i])) == 14:
+		print(i)
+		break