AoC 2020: day4

Signed-off-by: Ettore Dreucci <ettore.dreucci@gmail.com>

2020-python/solutions/day_1.py

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+"""AOC Day 1"""
+
+import pathlib
+import time
+
+def read_input(input_path: str) -> list:
+    """take input file path and return appropriate data structure"""
+    with open(input_path, 'r') as input_file:
+        entries = list()
+        for entry in input_file.readlines():
+            entries.append(int(entry))
+        return entries
+
+def part1(entries: list) -> int:
+    """part1 solver take a list of int and return an int"""
+    for x in entries:
+        complement = 2020 - x
+        if complement in entries:
+            return x * complement
+    return None
+
+def part2(entries: list) -> int:
+    """part2 solver take a list of int and return an int"""
+    for x, i in enumerate(entries):
+        for y in entries[i:]:
+            complement = 2020 - x - y
+            if complement in entries:
+                return x * y * complement
+    return None
+
+
+def main():
+    """main function"""
+    input_path = str(pathlib.Path.cwd()) + "/inputs/" + str(pathlib.Path(__file__).stem)
+    entries = read_input(input_path)
+    start_time = time.time()
+    print("Part 1: %d" % part1(entries))
+    print("Part 2: %d" % part2(entries))
+    end_time = time.time()
+    print("Execution time: %f" % (end_time-start_time))
+
+if __name__ == "__main__":
+    main()

2020-python/solutions/day_2.py

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+"""AOC Day 2"""
+
+import pathlib
+import time
+import re
+
+def read_input(input_path: str) -> list:
+    """take input file path and return appropriate data structure"""
+    with open(input_path, 'r') as input_file:
+        rules = list()
+        for entry in input_file.readlines():
+            splitted = re.split('-| |: ', entry)
+            rule = [int(splitted[0]), int(splitted[1]), splitted[2], splitted[3]]
+            rules.append(rule)
+        return rules
+
+
+def part1(entries: list) -> int:
+    """part1 solver take a list of tuples and return an int"""
+    correct_passwords = 0
+    for entry in entries:
+        occurrences = entry[3].count(entry[2])
+        if occurrences in range(entry[0], entry[1]+1):
+            correct_passwords += 1
+    return correct_passwords
+
+
+def part2(entries: list) -> int:
+    """part2 solver take a list of tuples and return an int"""
+    correct_passwords = 0
+    for entry in entries:
+        pos_1, pos_2, letter, password = entry[:]
+        if (password[pos_1-1] == letter) != (password[pos_2-1] == letter):
+            correct_passwords += 1
+    return correct_passwords
+
+def main():
+    """main function"""
+    input_path = str(pathlib.Path(__file__).resolve().parent.parent) + "/inputs/" + str(pathlib.Path(__file__).stem)
+    entries = read_input(input_path)
+    start_time = time.time()
+    print("Part 1: %d" % part1(entries))
+    print("Part 2: %d" % part2(entries))
+    end_time = time.time()
+    print("Execution time: %f" % (end_time-start_time))
+
+
+if __name__ == "__main__":
+    main()

2020-python/solutions/day_3.py

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+"""AOC Day 3"""
+
+import pathlib
+import time
+
+def read_input(input_path: str) -> list:
+    """take input file path and return appropriate data structure"""
+    with open(input_path, 'r') as input_file:
+        lines = list()
+        for line in input_file.readlines():
+            lines.append(line.strip())
+        return lines
+
+
+def slope_tree_check(lines: list, dx: int, dy: int) -> int:
+    """check how many trees would be encountered with a specific slope"""
+    x_pos = 0
+    y_pos = 0
+    trees_encountered = 0
+    line_length = len(lines[0])
+    while y_pos < len(lines):
+        if lines[y_pos][x_pos] == '#':
+            trees_encountered += 1
+        x_pos = (x_pos + dx) % line_length
+        y_pos += dy
+    return trees_encountered
+
+def part1(entries: list) -> int:
+    """part1 solver take a list of strings and return an int"""
+    return slope_tree_check(entries, 3, 1)
+
+
+def part2(entries: list) -> int:
+    """part2 solver take a list of tuples and return an int"""
+    slopes = [
+        (1, 1),
+        (3, 1),
+        (5, 1),
+        (7, 1),
+        (1, 2),
+        ]
+    prod = 1
+    for slope in slopes:
+        prod *= slope_tree_check(entries, slope[0], slope[1])
+    return prod
+
+def main():
+    """main function"""
+    input_path = str(pathlib.Path(__file__).resolve().parent.parent) + "/inputs/" + str(pathlib.Path(__file__).stem)
+    entries = read_input(input_path)
+    start_time = time.time()
+    print("Part 1: %d" % part1(entries))
+    print("Part 2: %d" % part2(entries))
+    end_time = time.time()
+    print("Execution time: %f" % (end_time-start_time))
+
+
+if __name__ == "__main__":
+    main()

2020-python/solutions/day_4.py

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+"""AOC Day 4"""
+
+import pathlib
+import time
+import re
+
+def read_input(input_path: str) -> list:
+    """take input file path and return appropriate data structure"""
+    with open(input_path, 'r') as input_file:
+        data = input_file.read()
+        entries = re.split(r"(?:\r?\n){2,}", data.strip())
+        passports = list()
+        for entry in entries:
+            passport = dict()
+            entry = entry.replace('\n', ' ')
+            data = entry.split(' ')
+            for field in data:
+                key, value = field.split(':')[:2]
+                passport[key] = value
+            passports.append(passport)
+        return passports
+
+def check_fields(passport: dict) -> bool:
+    """check if a passport contains all the required fields"""
+    required_fields = ["byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"]
+    for required_field in required_fields:
+        if required_field not in passport.keys():
+            return False
+        elif passport[required_field] == None or passport[required_field] == '':
+            return False
+    return True
+
+def check_data(passport: dict) -> bool:
+    """check if all passport fields contains correct data"""
+    return (1920 <= int(passport["byr"]) <= 2002 and
+        2010 <= int(passport["iyr"]) <= 2020 and
+        2020 <= int(passport["eyr"]) <= 2030 and
+        ((passport["hgt"].endswith("cm") and 150 <= int(passport["hgt"][:-2]) <= 193) or (passport["hgt"].endswith("in") and 59 <= int(passport["hgt"][:-2]) <= 76)) and
+        re.match(r"^#[0-9a-f]{6}$", passport["hcl"]) and
+        passport["ecl"] in ("amb", "blu", "brn", "gry", "grn", "hzl", "oth") and
+        re.match(r"^[0-9]{9}$", passport["pid"]))
+
+def part1(entries: list) -> int:
+    """part1 solver take a list of strings and return an int"""
+    valid_passports = 0
+    for passport in entries:
+        if check_fields(passport):
+            valid_passports += 1
+    return valid_passports
+
+
+def part2(entries: list) -> int:
+    """part2 solver take a list of tuples and return an int"""
+    valid_passports = 0
+    for passport in entries:
+        if check_fields(passport) and check_data(passport):
+            valid_passports += 1
+    return valid_passports
+
+def main():
+    """main function"""
+    input_path = str(pathlib.Path(__file__).resolve().parent.parent) + "/inputs/" + str(pathlib.Path(__file__).stem)
+    start_time = time.time()
+    entries = read_input(input_path)
+    print("Part 1: %d" % part1(entries))
+    print("Part 2: %d" % part2(entries))
+    end_time = time.time()
+    print("Execution time: %f" % (end_time-start_time))
+
+
+if __name__ == "__main__":
+    main()