diff --git a/python/day07.py b/python/day07.py
new file mode 100644
index 0000000..ecd29da
--- /dev/null
+++ b/python/day07.py
@@ -0,0 +1,48 @@
+import fileinput
+import re
+from collections import defaultdict
+
+network = {}
+reverse = defaultdict(list)
+
+for line in fileinput.input():
+    parent, children = line.strip().split(" contain ")
+    parent = parent[:-5]
+    children = children.rstrip(".").split(", ")
+    children = [
+        child.rstrip("s")[:-4].split(" ", 1)
+        for child in children
+        if "no other" not in child
+    ]
+    children = [(int(n), c) for n, c in children]
+
+    network[parent] = children
+    for n, child in children:
+        reverse[child].append((n, parent))
+
+reverse = dict(reverse)
+
+shiny_gold_bags = set()
+stack = ["shiny gold"]
+while stack:
+    color = stack.pop()
+    if color not in reverse:
+        continue
+    for _, parent in reverse[color]:
+        stack.append(parent)
+        shiny_gold_bags.add(parent)
+
+print("part 1:", len(shiny_gold_bags))
+
+part2 = 0
+stack = [(1, "shiny gold")]
+while stack:
+    n, color = stack.pop()
+    part2 += n
+
+    children = network[color]
+    for m, child in children:
+        stack.append((n * m, child))
+part2 -= 1
+
+print("part 2:", part2)
diff --git a/python/day09-a.py b/python/day09-a.py
new file mode 100644
index 0000000..3fb0ccd
--- /dev/null
+++ b/python/day09-a.py
@@ -0,0 +1,22 @@
+import fileinput
+import itertools
+
+N = 25
+
+numbers = []
+for line in fileinput.input():
+    numbers.append(int(line))
+
+for i in range(N, len(numbers)):
+    found = False
+    for j in numbers[i - N:i]:
+        for k in numbers[i - N:i]:
+            if j == k:
+                continue
+            if j + k == numbers[i]:
+                found = True
+    if not found:
+        print(numbers[i])
+        break
+
+
diff --git a/python/day09-b.py b/python/day09-b.py
new file mode 100644
index 0000000..f6d441d
--- /dev/null
+++ b/python/day09-b.py
@@ -0,0 +1,22 @@
+import fileinput
+import itertools
+import sys
+
+N = 25
+
+numbers = []
+for line in fileinput.input():
+    numbers.append(int(line))
+
+for i in range(N, len(numbers)):
+    target = 25918798
+    #target=127
+    for j in range(i - N,i):
+        for k in range(j+ 1, i):
+            nn = numbers[j:k]
+            if sum(nn) == target:
+                print(max(nn) + min(nn))
+                sys.exit(0)
+
+
+
diff --git a/python/day10.py b/python/day10.py
new file mode 100644
index 0000000..bd46b75
--- /dev/null
+++ b/python/day10.py
@@ -0,0 +1,38 @@
+import fileinput
+import itertools
+from collections import deque
+
+adapters = [0]
+for line in fileinput.input():
+    adapters.append(int(line))
+adapters.sort()
+adapters.append(adapters[-1] + 3)
+
+one = 0
+three = 0
+
+for (fr, to) in zip(adapters[:-1], adapters[1:]):
+    if to - fr == 1:
+        one += 1
+    elif to - fr == 3:
+        three += 1
+    print(fr, to)
+
+print(one, three, one * three)
+paths = [0] * len(adapters)
+paths[0] = 1
+
+ways = 1
+for i, value in enumerate(adapters[:-1]):
+    try:
+        if adapters[i + 1] <= value + 3:
+            paths[i + 1] += paths[i]
+        if adapters[i + 2] <= value + 3:
+            paths[i + 2] += paths[i] 
+        if adapters[i + 3] <= value + 3:
+            paths[i + 3] += paths[i]
+    except IndexError:
+        pass
+
+print(paths)
+print(paths[-1])
diff --git a/python/day11.py b/python/day11.py
new file mode 100644
index 0000000..7128d78
--- /dev/null
+++ b/python/day11.py
@@ -0,0 +1,118 @@
+import fileinput
+from pprint import pprint
+from copy import deepcopy
+
+layout = []
+for line in fileinput.input():
+    if line.strip():
+        layout.append(list(line.strip()))
+
+part1 = -1
+old_layout = deepcopy(layout)
+row_length = len(old_layout[0])
+
+while True:
+    new_layout = [[None] * len(row) for row in old_layout]
+    for y in range(len(old_layout)):
+        for x in range(len(old_layout[0])):
+            if old_layout[y][x] == ".":
+                new_layout[y][x] = old_layout[y][x]
+                continue
+
+            count = sum(
+                (
+                    x >= 1 and old_layout[y][x - 1] == "#",
+                    x < row_length - 1 and old_layout[y][x + 1] == "#",
+                )
+            )
+
+            if y >= 1:
+                count += sum(
+                    (
+                        x >= 1 and old_layout[y - 1][x - 1] == "#",
+                        old_layout[y - 1][x] == "#",
+                        x < row_length - 1 and old_layout[y - 1][x + 1] == "#",
+                    )
+                )
+
+            if y < len(layout) - 1:
+                count += sum(
+                    (
+                        x >= 1 and old_layout[y + 1][x - 1] == "#",
+                        old_layout[y + 1][x] == "#",
+                        x < row_length - 1 and old_layout[y + 1][x + 1] == "#",
+                    )
+                )
+
+            if count == 0:
+                new_layout[y][x] = "#"
+            elif count >= 4:
+                new_layout[y][x] = "L"
+            else:
+                new_layout[y][x] = old_layout[y][x]
+
+    new_part1 = sum(sum(s == "#" for s in row) for row in new_layout)
+    if part1 == new_part1:
+        break
+    part1 = new_part1
+
+    old_layout = new_layout
+
+print(part1)
+
+
+part2 = -1
+old_layout = deepcopy(layout)
+
+
+def get(x, y, dx, dy):
+    try:
+        x += dx
+        y += dy
+        while old_layout[y][x] == ".":
+            if x < 0 or y < 0:
+                raise IndexError
+            x += dx
+            y += dy
+    except:
+        return "."
+
+    return old_layout[y][x]
+
+
+while True:
+    new_layout = [[None] * len(row) for row in old_layout]
+    for y in range(1, len(old_layout) - 1):
+        for x in range(1, len(old_layout[0]) - 1):
+            if old_layout[y][x] == ".":
+                new_layout[y][x] = old_layout[y][x]
+                continue
+
+            count = sum(
+                (
+                    get(x, y, -1, -1) == "#",
+                    get(x, y, -1, 0) == "#",
+                    get(x, y, -1, 1) == "#",
+                    get(x, y, 0, -1) == "#",
+                    get(x, y, 0, 1) == "#",
+                    get(x, y, 1, -1) == "#",
+                    get(x, y, 1, 0) == "#",
+                    get(x, y, 1, 1) == "#",
+                )
+            )
+
+            if count == 0:
+                new_layout[y][x] = "#"
+            elif count >= 5:
+                new_layout[y][x] = "L"
+            else:
+                new_layout[y][x] = old_layout[y][x]
+
+    new_part2 = sum(sum(s == "#" for s in row) for row in new_layout)
+    if part2 == new_part2:
+        break
+    part2 = new_part2
+
+    old_layout = new_layout
+
+print(part2)
diff --git a/python/day13.py b/python/day13.py
new file mode 100644
index 0000000..f49c284
--- /dev/null
+++ b/python/day13.py
@@ -0,0 +1,48 @@
+import fileinput
+
+input = fileinput.input()
+
+arrival = int(next(input))
+buses = [None if bus == "x" else int(bus) for bus in next(input).split(",")]
+print(arrival, buses)
+
+remainders = [-(arrival % (-bus)) if bus else float("inf") for bus in buses]
+print(remainders)
+
+print(
+    "Part 1:",
+    min(enumerate(buses), key=lambda x: remainders[x[0]])[1] * min(remainders),
+)
+
+def combine(a_period, a_offset, b_period, b_offset):
+    gcd, s, _ = egcd(a_period, b_period)
+    diff = a_offset - b_offset
+    diff_quot, dif_rem = divmod(diff, gcd)
+    assert(dif_rem == 0)
+
+    combined_period = a_period // gcd * b_period
+    combined_offset = (a_offset - s * diff_quot * a_period) % combined_period
+    return combined_period, combined_offset
+
+def egcd(a, b):
+    r_, r = a, b
+    s_, s = 1, 0
+    t_, t = 0, 1
+    while r:
+        quot, rem = divmod(r_, r)
+        r_, r = r, rem
+        s_, s = s, (s_ - quot * s)
+        t_, t = t, (t_ - quot * t)
+    return r_, s_, t_
+
+period = 1
+offset = 0
+
+for i, bus in enumerate(buses):
+    if bus is None:
+        continue
+
+    period, offset = combine(period, offset, bus, i)
+    print(i, bus, period, offset)
+
+print(-offset % period)
diff --git a/python/day14.py b/python/day14.py
new file mode 100644
index 0000000..b736e9a
--- /dev/null
+++ b/python/day14.py
@@ -0,0 +1,55 @@
+import fileinput
+from pprint import pprint
+from typing import List
+
+mem = {}
+for line in fileinput.input():
+    l, r = line.strip().split(" = ")
+    if l == "mask":
+        and_mask = int(r.replace("X", "1"), base=2)
+        or_mask = int(r.replace("X", "0"), base=2)
+    else:
+        value = int(r)
+        value &= and_mask
+        value |= or_mask
+        mem[int(l[4:-1])] = value
+
+print(sum(mem.values()))
+
+def recurse(s: str) -> List[str]:
+    x = s.find("X")
+    if x == -1:
+        return [s]
+
+    s0 = s[:x] + '0' + s[x + 1:]
+    s1 = s[:x] + '1' + s[x + 1:]
+
+    return [*recurse(s0), *recurse(s1)]
+
+mem = {}
+for line in fileinput.input():
+    l, r = line.strip().split(" = ")
+
+    if l == "mask":
+        mask = r
+        or_mask = int(r.replace("X", "0"), base=2)
+
+        floatings = recurse(r.replace("0", "_").replace("1", "_"))
+        and_masks = [int(v.replace("_", "1"), 2) for v in floatings]
+        or_masks = [int(v.replace("_", "0"), 2) for v in floatings]
+
+        assert(len(and_masks) == 2 ** r.count("X"))
+        assert(len(or_masks) == 2 ** r.count("X"))
+    else:
+        orig_address = int(l[4:-1])
+        orig_address |= or_mask
+
+        for (and_, or_) in zip(and_masks, or_masks):
+            address = orig_address
+            address &= and_
+            address |= or_
+            mem[address] = int(r)
+            assert(address >= 0)
+
+assert(not [k for k in mem.keys() if k < 0])
+print(sum(mem.values()))