4 files changed, 269 insertions, 0 deletions
diff --git a/users/Profpatsch/advent-of-code/2020/01/main.py b/users/Profpatsch/advent-of-code/2020/01/main.py
new file mode 100644
index 000000000000..e636017a54d5
--- /dev/null
+++ b/users/Profpatsch/advent-of-code/2020/01/main.py
@@ -0,0 +1,22 @@
+import sys
+
+l = []
+with open('./input', 'r') as f:
+    for line in f:
+        l.append(int(line))
+
+s = set(l)
+
+res=None
+for el in s:
+    for el2 in s:
+        if (2020-(el+el2)) in s:
+            res=(el, el2, 2020-(el+el2))
+            break
+
+if res == None:
+    sys.exit("could not find a number that adds to 2020")
+
+print(res)
+
+print(res[0] * res[1] * res[2])
diff --git a/users/Profpatsch/advent-of-code/2020/02/main.py b/users/Profpatsch/advent-of-code/2020/02/main.py
new file mode 100644
index 000000000000..e3b27c382a21
--- /dev/null
+++ b/users/Profpatsch/advent-of-code/2020/02/main.py
@@ -0,0 +1,77 @@
+import sys
+
+def parse(line):
+    a = line.split(sep=" ", maxsplit=1)
+    assert len(a) == 2
+    fromto = a[0].split(sep="-")
+    assert len(fromto) == 2
+    (from_, to) = (int(fromto[0]), int(fromto[1]))
+    charpass = a[1].split(sep=": ")
+    assert len(charpass) == 2
+    char = charpass[0]
+    assert len(char) == 1
+    pass_ = charpass[1]
+    assert pass_.endswith("\n")
+    pass_ = pass_[:-1]
+    return {
+        "from": from_,
+        "to": to,
+        "char": char,
+        "pass": pass_
+    }
+
+def char_in_pass(char, pass_):
+    return pass_.count(char)
+
+def validate_01(entry):
+    no = char_in_pass(entry["char"], entry["pass"])
+    if no < entry["from"]:
+        return { "too-small": entry }
+    elif no > entry["to"]:
+        return { "too-big": entry }
+    else:
+        return { "ok": entry }
+
+def char_at_pos(char, pos, pass_):
+    assert pos <= len(pass_)
+    return pass_[pos-1] == char
+
+def validate_02(entry):
+    one = char_at_pos(entry["char"], entry["from"], entry["pass"])
+    two = char_at_pos(entry["char"], entry["to"], entry["pass"])
+    if one and two:
+        return { "both": entry }
+    elif one:
+        return { "one": entry }
+    elif two:
+        return { "two": entry }
+    else:
+        return { "none": entry }
+
+
+res01 = []
+res02 = []
+with open("./input", 'r') as f:
+    for line in f:
+        p = parse(line)
+        res01.append(validate_01(p))
+        res02.append(validate_02(p))
+
+count01=0
+for r in res01:
+    print(r)
+    if r.get("ok", False):
+        count01=count01+1
+
+count02=0
+for r in res02:
+    print(r)
+    if r.get("one", False):
+        count02=count02+1
+    elif r.get("two", False):
+        count02=count02+1
+    else:
+        pass
+
+print("count 1: {}".format(count01))
+print("count 2: {}".format(count02))
diff --git a/users/Profpatsch/advent-of-code/2020/03/main.py b/users/Profpatsch/advent-of-code/2020/03/main.py
new file mode 100644
index 000000000000..4d6baf946c3e
--- /dev/null
+++ b/users/Profpatsch/advent-of-code/2020/03/main.py
@@ -0,0 +1,66 @@
+import itertools
+import math
+
+def tree_line(init):
+    return {
+        "init-len": len(init),
+        "known": '',
+        "rest": itertools.repeat(init)
+    }
+
+def tree_line_at(pos, tree_line):
+    needed = (pos + 1) - len(tree_line["known"])
+    # internally advance the tree line to the position requested
+    if needed > 0:
+        tree_line["known"] = tree_line["known"] \
+          + ''.join(
+            itertools.islice(
+                tree_line["rest"],
+                1+math.floor(needed / tree_line["init-len"])))
+    # print(tree_line)
+    return tree_line["known"][pos] == '#'
+
+def tree_at(linepos, pos, trees):
+    return tree_line_at(pos, trees[linepos])
+
+def slope_positions(trees, right, down):
+    line = 0
+    pos = 0
+    while line < len(trees):
+        yield (line, pos)
+        line = line + down
+        pos = pos + right
+
+trees = []
+with open("./input", 'r') as f:
+    for line in f:
+        line = line.rstrip()
+        trees.append(tree_line(line))
+
+# print(list(itertools.islice(trees[0], 5)))
+# print(list(map(
+#     lambda x: tree_at(0, x, trees),
+#     range(100)
+# )))
+# print(list(slope_positions(trees, right=3, down=1)))
+
+def count_slope_positions(trees, slope):
+    count = 0
+    for (line, pos) in slope:
+        if tree_at(line, pos, trees):
+            count = count + 1
+    return count
+
+print(
+        count_slope_positions(trees, slope_positions(trees, right=1, down=1))
+    *
+        count_slope_positions(trees, slope_positions(trees, right=3, down=1))
+    *
+        count_slope_positions(trees, slope_positions(trees, right=5, down=1))
+    *
+        count_slope_positions(trees, slope_positions(trees, right=7, down=1))
+    *
+        count_slope_positions(trees, slope_positions(trees, right=1, down=2))
+)
+
+# I realized I could have just used a modulo instead …
diff --git a/users/Profpatsch/advent-of-code/2020/04/main.py b/users/Profpatsch/advent-of-code/2020/04/main.py
new file mode 100644
index 000000000000..36bbed7146d6
--- /dev/null
+++ b/users/Profpatsch/advent-of-code/2020/04/main.py
@@ -0,0 +1,104 @@
+import sys
+import itertools
+import re
+import pprint
+
+def get_entry(fd):
+    def to_dict(keyval):
+        res = {}
+        for (k, v) in keyval:
+            assert k not in res
+            res[k] = v
+        return res
+
+    res = []
+    for line in fd:
+        if line == "\n":
+            yield to_dict(res)
+            res = []
+        else:
+            line = line.rstrip()
+            items = line.split(" ")
+            for i in items:
+                res.append(i.split(":", maxsplit=2))
+
+def val_hgt(hgt):
+    m = re.fullmatch(r'([0-9]+)(cm|in)', hgt)
+    if m:
+        (i, what) = m.group(1,2)
+        i = int(i)
+        if what == "cm":
+            return i >= 150 and i <= 193
+        elif what == "in":
+            return i >= 59 and i <= 76
+        else:
+            return False
+
+required_fields = [
+    { "name": "byr",
+      "check": lambda s: int(s) >= 1920 and int(s) <= 2002
+    },
+    { "name": "iyr",
+      "check": lambda s: int(s) >= 2010 and int(s) <= 2020
+    },
+    { "name": "eyr",
+      "check": lambda s: int(s) >= 2020 and int(s) <= 2030,
+    },
+    { "name": "hgt",
+      "check": lambda s: val_hgt(s)
+    },
+    { "name": "hcl",
+      "check": lambda s: re.fullmatch(r'#[0-9a-f]{6}', s)
+    },
+    { "name": "ecl",
+      "check": lambda s: re.fullmatch(r'amb|blu|brn|gry|grn|hzl|oth', s)
+    },
+    { "name": "pid",
+      "check": lambda s: re.fullmatch(r'[0-9]{9}', s)
+    },
+    # we should treat it as not required
+    # "cid"
+]
+
+required_dict = {}
+for f in required_fields:
+    required_dict[f["name"]] = f
+
+def validate(keyval):
+    if keyval[0] not in required_dict:
+        return { "ok": keyval }
+    if required_dict[keyval[0]]["check"](keyval[1]):
+        return { "ok": keyval }
+    else:
+        return { "validation": keyval }
+
+def all_fields(entry):
+    missing = []
+    for r in required_dict:
+        if r not in e:
+            missing.append(r)
+    if missing == []:
+        return { "ok": entry }
+    else:
+        return { "missing": missing }
+
+count=0
+for e in get_entry(sys.stdin):
+    a = all_fields(e)
+    if a.get("ok", False):
+        res = {}
+        bad = False
+        for keyval in e.items():
+            r = validate(keyval)
+            if r.get("validation", False):
+                bad = True
+            res[keyval[0]] = r
+        if bad:
+            pprint.pprint({ "validation": res })
+        else:
+            pprint.pprint({ "ok": e })
+            count = count+1
+    else:
+        pprint.pprint(a)
+
+print(count)