pub fn parse(input: &str) -> Vec<[i32; 63]>Expand description
Parse a snailfish number into an implicit binary tree stored in an array.
Since no number will greater than 9 initially we can consider each character individually.
[ means moves down a level to parse children, , means move from left to right node,
] means move up a level to return to parent and a digit from 0-9 creates a leaf node
with that value.