Given a directed graph defined where aaa: you hhh means aaa is connected to you and hhh, how many paths are there from you to out.

You are given a map like this:

.......S.......
...............
.......^.......
...............
......^.^......
...............

A laser shines from the top S and splits each time it hits a ^, making this:

.......S.......
.......|.......
......|^|......
......|.|......
.....|^|^|.....
.....|.|.|.....

The two lasers in the center of this example merge to count as one laser.

Count how many times lasers hit splitters.

Given a heightmap (0 to 9), for each 0 count how many 9 you can reach on paths that only ever increase height by exactly 1 at a time. Sum these values.