71 lines
1.8 KiB
Python
71 lines
1.8 KiB
Python
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with open('input08', 'r') as file:
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lines = [(lambda x: (x[0],int(x[1])))(line.strip().split()) for line in file.readlines()]
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def f_acc(regs, x):
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regs['acc'] += x
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regs['ip'] += 1
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def f_jmp(regs, x):
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regs['ip'] += x
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def f_nop(regs, x):
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regs['ip'] += 1
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fns = {'acc': f_acc, 'jmp': f_jmp, 'nop': f_nop}
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inst_swap = {'jmp': 'nop', 'nop': 'jmp', 'acc': 'acc'}
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regs = {'ip': 0, 'acc': 0}
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executed_ips = set()
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while(True):
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if regs['ip'] in executed_ips:
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print(f'Part 1: {regs["acc"]}')
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break
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executed_ips.add(regs['ip'])
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inst, x = lines[regs['ip']]
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fns[inst](regs, x)
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# This was an attempt to do a clever backtracking approach to minimize runs. It didn't work properly.
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#regs = {'ip': 0, 'acc': 0}
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#stacktrace = []
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#executed_ips = set()
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#flipped_ips = set()
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#while True:
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#if regs['ip'] in executed_ips:
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#while regs['ip'] in flipped_ips:
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#regs, executed_ips = stacktrace.pop()
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#print(f'loop reached, backtracking to state {regs}')
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#inst, x = lines[regs['ip']]
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#inst = inst_swap[inst]
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#flipped_ips.add(regs['ip'])
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#else:
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#executed_ips.add(regs['ip'])
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#inst, x = lines[regs['ip']]
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#stacktrace.append((regs.copy(), executed_ips.copy()))
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#fns[inst](regs, x)
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#if regs['ip'] >= len(lines):
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#print('Program completed successfully!')
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#break
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# Turns out the problemspace is so low that bruteforce is king anyway
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def simulate(flipped_ip):
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regs = {'ip': 0, 'acc': 0}
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executed_ips = set()
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while True:
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if regs['ip'] in executed_ips:
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return False
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executed_ips.add(regs['ip'])
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inst, x = lines[regs['ip']]
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if regs['ip'] == flipped_ip:
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inst = inst_swap[inst]
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fns[inst](regs, x)
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if regs['ip'] >= len(lines):
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return regs['acc']
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for i, (inst, x) in enumerate(lines):
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if inst != 'acc':
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result = simulate(i)
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if result:
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print(f'Part 2: {result}')
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break
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