452 B
452 B
Day 3
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Today's language: C
All the characters (the Elf's items) occuring in (half) a line (backpack) are stored as bits in an unsigned long, duplicate characters can then be determined by bitwise and-ing these numbers.
# Find the item type that appears in both compartments of each rucksack. What is the sum of the priorities of those item types?
gcc main.c -o day3
./day3