Find an algorithm.

神圣的贞德

A sequence of numbers, such as: 1, 2, 3, 5, 7, 8, 9

The program is required to complete such functions, read this number sequence in a loop, and form this number sequence into a string. The format is required: "1-3,5,7-9". That is, the increasing number sequence is in nm Performance, otherwise it is expressed as n, m.

Is there any good algorithm ?! C #

sometimess

If it's in order, can't iterate over it?

A variable int pre holds the previous number, and it is checked first when it encounters the current number int cur.

if cur-pre == 1 then

pre = cur
next

else

print "-" + pre + "," + cur

end if