Solution for Advent of Code 2016 - Day 23: Safe Cracking

Link to the puzzle text

Part 1

In this puzzle we have the same pseudo-assembly as in day 12. A new opcode "tgl" is added. This opcode modifies the source code itself by switching an opcode specified by an offset. We are again given a program and asked to find the output for a given input number.

We reused the answer from day 12 and implemented the new opcode. For speeding up the execution, we also replaced the regex run every cycle with a simple string splitting and comparison. This was enough to get the answer for part 1.

Part 2

For part 2, we are given a different input for the program and are again asked for the output. Simply running the program took to long, so a different approach was needed. Slowly increasing the input number yielded a sequence which was recognized as a factorial with a constant on top. This way we could give an explicit formula. Since the exact constant probably varies from input to input, we calculate it from the answer of part 1.

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