|| ||Code Submission Evaluation System
CSES Problem Set
Task | Statistics
CSES - Course ScheduleCSES - Course Schedule
|Time limit:||1.00 s
||Memory limit:||512 MB|
You have to complete $n$ courses. There are $m$ requirements of the form "course $a$ has to be completed before course $b$". Your task is to find an order in which you can complete the courses.
The first input line has two integers $n$ and $m$: the number of courses and requirements. The courses are numbered $1,2,\dots,n$.
After this, there are $m$ lines describing the requirements. Each line has two integers $a$ and $b$: course $a$ has to be completed before course $b$.
Print an order in which you can complete the courses. You can print any valid order that includes all the courses.
If there are no solutions, print "IMPOSSIBLE".
- $1 \le n \le 10^5$
- $1 \le m \le 2 \cdot 10^5$
- $1 \le a,b \le n$
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