busnumbers

Bus Numbers

ID: busnumbers

Difficulty: 2.5

CPU Time: 1 second

Memory: 1024 MB

Solution

For this problem, one can take in all the stops, and sort them in ascending order. Then, traverse the stops and group them: if the current stop is 1 greater than the "current" group's last number, or the current is empty, add it; otherwise, the current group is complete and can be added to some group of groups. Then, output all the groups: only the front if there is one number, otherwise the front and back, which are separated by a space if there are only two numbers in the group, "-" otherwise.