AoC 2020: day14

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

2020-python/solutions/day_14.py

@@ -0,0 +1,109 @@
+"""AOC 2020 Day 14"""
+
+import pathlib
+import time
+import re
+import itertools
+
+TEST_INPUT = """mask = XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X
+mem[8] = 11
+mem[7] = 101
+mem[8] = 0"""
+
+TEST_INPUT_2 = """mask = 000000000000000000000000000000X1001X
+mem[42] = 100
+mask = 00000000000000000000000000000000X0XX
+mem[26] = 1"""
+
+def read_input(input_path: str) -> str:
+    """take input file path and return a str with the file's content"""
+    with open(input_path, 'r') as input_file:
+        input_data = input_file.read().strip()
+        return input_data
+
+def extract(input_data: str) -> list:
+    """take input data and return the appropriate data structure"""
+    entries = list()
+    mem_rexp = re.compile(r'mem\[(\d+)\] = (\d+)')
+    for line in input_data.split('\n'):
+        if line.startswith('mask'):
+            entry = {
+                'type': 'mask',
+                'value': line[7:].rstrip(),
+            }
+        else:
+            entry = {
+                'type': 'mem',
+                'value': mem_rexp.match(line).groups(),
+            }
+        entries.append(entry)
+    return entries
+
+def generate_addresses(addr: str, mask: str) -> list:
+    """generate all possible addresses from floating mask"""
+    generator_bits = list()
+    addresses = list()
+    addr = format(int(addr), '036b')
+    for addr_bit, mask_bit in zip(addr, mask):
+        if mask_bit == '0':
+            generator_bits.append(addr_bit)
+        elif mask_bit == '1':
+            generator_bits.append('1')
+        else:
+            generator_bits.append('01')
+    for address in itertools.product(*generator_bits):
+        addresses.append(int(''.join(address), 2))
+    return addresses
+
+def part1(entries: dict) -> int:
+    """part1 solver"""
+    mem = dict()
+    mask_keep0s = 0
+    mask_keep1s = 0
+    for entry in entries:
+        if entry['type'] == 'mask':
+            mask = entry['value']
+            mask_keep0s = int(mask.replace('X', '1'), 2)
+            mask_keep1s = int(mask.replace('X', '0'), 2)
+        else:
+            addr, value = entry['value']
+            mem[addr] = (int(value) & mask_keep0s) | mask_keep1s
+    return sum(mem.values())
+
+def part2(entries: tuple) -> int:
+    """part2 solver"""
+    mem = dict()
+    mask = ''
+    for entry in entries:
+        if entry['type'] == 'mask':
+            mask = entry['value']
+        else:
+            addr, value = entry['value']
+            for address in generate_addresses(addr, mask):
+                mem[address] = int(value)
+    return sum(mem.values())
+
+def test_input_day_14():
+    """pytest testing function"""
+    entries = extract(TEST_INPUT)
+    assert part1(entries) == 165
+    entries = extract(TEST_INPUT_2)
+    assert part2(entries) == 208
+
+def test_bench_day_14(benchmark):
+    """pytest-benchmark function"""
+    benchmark(main)
+
+def main():
+    """main function"""
+    input_path = str(pathlib.Path(__file__).resolve().parent.parent) + "/inputs/" + str(pathlib.Path(__file__).stem)
+    start_time = time.time()
+    input_data = read_input(input_path)
+    entries = extract(input_data)
+    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()