|| ||Code Submission Evaluation System
CSES Problem Set
Task | Statistics
CSES - Distinct RoutesCSES - Distinct Routes
|Time limit:||1.00 s
||Memory limit:||512 MB|
A game consists of $n$ rooms and $m$ teleporters. At the beginning of each day, you start in room $1$ and you have to reach room $n$.
You can use each teleporter at most once during the game. How many days can you play if you choose your routes optimally?
The first input line has two integers $n$ and $m$: the number of rooms and teleporters. The rooms are numbered $1,2,\dots,n$.
After this, there are $m$ lines describing the teleporters. Each line has two integers $a$ and $b$: there is a teleporter from room $a$ to room $b$.
There are no two teleporters whose starting and ending room are the same.
First print an integer $k$: the maximum number of days you can play the game. Then, print $k$ route descriptions according to the example. You can print any valid solution.
- $2 \le n \le 500$
- $1 \le m \le 1000$
- $1 \le a,b \le n$
1 2 6
1 3 4 6