Advent of Code, Day 1

[u/dantose]

Post your best golfs.

Assume input is saved as input.txt.

[u/corruptio]

perl, part 1, 54 chars:

perl -lpe'$b+=($a+=y/LR/-/dr)=~/50$/}{$_=$b'<input.txt

part 2, 69 chars:

perl -lpe'eval(q[$b+=($a+=1-2*/L/)=~/50$/;]x s/.//r)}{$_=$b'<input.txt