84 lines
1.6 KiB
Python
84 lines
1.6 KiB
Python
import sys
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# PART 1
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def load_polymer(filename):
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pols = []
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with open(filename, "r") as f:
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for line in f:
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pols.append(list(line[:-1]))
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return pols
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def naive_react(pol):
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for i in range(len(pol) - 1):
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if pol[i].lower() == pol[i+1].lower() and pol[i] != pol[i+1]:
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print("Naive react says: More reacting is possible.")
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def react(pol):
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while True:
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i = 0
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while i < len(pol) - 1:
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pol_cur, pol_next = pol[i], pol[i+1]
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if pol_cur.lower() == pol_next.lower() and pol_cur != pol_next:
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del pol[i]
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del pol[i]
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i = max(0, i - 1)
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else:
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i += 1
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else:
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return
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#def react(pol):
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# start = 0
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# while True:
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# i = start
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# while i < len(pol) - 1:
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# if pol[i].lower() == pol[i+1].lower() and pol[i] != pol[i+1]:
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# del pol[i]
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# del pol[i]
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# start = max(0, start - 1)
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# break
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# elif i == start + 1:
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# start = i
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# i += 1
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# else:
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# return
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def result(pol):
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l = pol.copy()
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#print("".join(l))
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react(l)
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#print("->", "".join(l))
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naive_react(l)
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return len(l)
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# PART 2
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def removable_chars(pol):
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return set(c.lower() for c in pol)
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def remove(pol, char):
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return [c for c in pol if c.lower() != char.lower()]
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def find_obstructing(pol):
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results = []
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chars = removable_chars(pol)
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for c in sorted(chars):
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l = remove(pol, c)
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n = result(l)
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print("Removed", c, "-> length", n)
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results.append(n)
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return min(results)
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def main(filename):
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print(f"Solutions for {filename}")
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pols = load_polymer(filename)
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for pol in pols:
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length = result(pol)
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print(f"Part 1: {length}")
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best_result = find_obstructing(pol)
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print(f"Part 2: {best_result}")
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if __name__ == "__main__":
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for filename in sys.argv[1:]:
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main(filename)
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