My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2016/21
+189
+87
2016/day21.py
+87
2016/day21.py
···
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import fileinput
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from collections import deque
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from utils import parse_line
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def scramble(data, operations, unscramble=False):
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data = deque(data)
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if unscramble:
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operations.reverse()
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for line in operations:
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if line.startswith('swap position'):
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x, y = parse_line(r'swap position (\d+) with position (\d+)', line)
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data[x], data[y] = data[y], data[x]
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elif line.startswith('swap letter'):
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x, y = parse_line(r'swap letter (\w+) with letter (\w+)', line)
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data = deque(''.join(data).replace(x, '_').replace(y, x).replace('_', y))
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elif line.startswith('rotate based'):
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x = line.split()[-1]
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tmp = ''.join(data)
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if not unscramble:
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i = tmp.index(x)
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data.rotate(i + (2 if i >= 4 else 1))
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else:
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# Keep trying rotation candidates until one is valid
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curr = deque(data)
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while True:
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curr.rotate(1)
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post = ''.join(curr)
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idx = post.index(x)
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tmp = deque(data)
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tmp.rotate(-(idx + (2 if idx >= 4 else 1)))
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pre = ''.join(tmp)
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if pre == post:
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data = deque(pre)
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break
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elif line.startswith('rotate'):
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lr, x = parse_line(r'rotate (\w+) (\d+) step', line)
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if (unscramble and lr == 'right') or (not unscramble and lr == 'left'):
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x = -x
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data.rotate(x)
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elif line.startswith('reverse'):
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x, y = parse_line(r'reverse positions (\d+) through (\d+)', line)
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tmp = ''.join(data)
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tmp = tmp[:x] + ''.join(reversed(tmp[x:y+1])) + tmp[y+1:]
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data = deque(tmp)
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elif line.startswith('move'):
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x, y = parse_line(r'move position (\d+) to position (\d+)', line)
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if unscramble:
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x, y = y, x
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tmp = ''.join(data)
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# Extract the character
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c = tmp[x]
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tmp = tmp[:x] + tmp[x+1:]
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# Reinsert it
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tmp = tmp[:y] + c + tmp[y:]
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data = deque(tmp)
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return ''.join(data)
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if __name__ == '__main__':
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operations = [line.strip() for line in fileinput.input()]
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print 'Result of scrambling abcdefgh:', scramble('abcdefgh', operations, False)
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print 'Unscrambled version of fbgdceah:', scramble('fbgdceah', operations, unscramble=True)
+100
2016/inputs/21.txt
+100
2016/inputs/21.txt
···
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move position 2 to position 6
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move position 0 to position 5
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move position 6 to position 4
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reverse positions 3 through 7
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move position 1 to position 7
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swap position 6 with position 3
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swap letter g with letter b
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swap position 2 with position 3
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move position 4 to position 3
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move position 6 to position 3
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swap position 4 with position 1
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swap letter b with letter f
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reverse positions 3 through 4
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swap letter f with letter e
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reverse positions 2 through 7
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rotate based on position of letter h
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rotate based on position of letter a
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rotate based on position of letter e
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rotate based on position of letter h
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rotate based on position of letter c
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move position 5 to position 7
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swap letter a with letter d
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move position 5 to position 6
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swap position 4 with position 0
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swap position 4 with position 6
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rotate left 6 steps
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rotate right 4 steps
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rotate right 5 steps
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swap letter f with letter e
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swap position 2 with position 7
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rotate based on position of letter e
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move position 4 to position 5
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swap position 4 with position 2
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rotate right 1 step
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swap letter b with letter f
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rotate based on position of letter b
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reverse positions 3 through 5
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move position 3 to position 1
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rotate based on position of letter g
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swap letter c with letter e
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swap position 7 with position 3
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move position 0 to position 3
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rotate right 6 steps
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reverse positions 1 through 3
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swap letter d with letter e
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reverse positions 3 through 5
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move position 0 to position 3
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swap letter c with letter e
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move position 2 to position 7
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swap letter g with letter b
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rotate right 0 steps
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reverse positions 1 through 3
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swap letter h with letter d
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move position 4 to position 0
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move position 6 to position 3
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swap letter a with letter c
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reverse positions 3 through 6
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swap letter h with letter g
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move position 7 to position 2
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rotate based on position of letter h
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swap letter b with letter h
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reverse positions 2 through 6
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move position 6 to position 7
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rotate based on position of letter a
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rotate right 7 steps
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reverse positions 1 through 6
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move position 1 to position 6
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rotate based on position of letter g
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rotate based on position of letter d
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move position 0 to position 4
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rotate based on position of letter e
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rotate based on position of letter d
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rotate based on position of letter a
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rotate based on position of letter a
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rotate right 4 steps
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rotate based on position of letter b
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reverse positions 0 through 4
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move position 1 to position 7
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rotate based on position of letter e
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move position 1 to position 7
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swap letter f with letter h
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move position 5 to position 1
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rotate based on position of letter f
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reverse positions 0 through 1
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move position 2 to position 4
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rotate based on position of letter a
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swap letter b with letter d
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move position 6 to position 0
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swap letter e with letter b
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rotate right 7 steps
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move position 2 to position 7
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rotate left 4 steps
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swap position 6 with position 1
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move position 3 to position 5
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rotate right 7 steps
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reverse positions 0 through 6
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swap position 2 with position 1
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reverse positions 4 through 6
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rotate based on position of letter g
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move position 6 to position 4