You have an elevation map and you want to know the shortest climbing route.
The map is given as a list of strings.
- 0 : plain ( elevation is 0)
- 1-9 : hill (number is elevation)
"mountain" is adjacent (only 4 directions) hill group.
- It consists of two or more hills.
- Isolated hill is not mountain.
Start is top-left. Goal is bottom-right....