OJ Board

maybe you divide zero or a very small real number, or sqrt(negative number)

exhausted search is OK if you prune some impossible status. my program run very fast

what the answer if source and destination is the same ?

check this case:

1

4
0 9
0 9
0 9
1 9

"long long" is not enough, you need to calc in big numbers

cardinal is also avail in GPC

look at this example :

char s[maxlen];
cin.getline(s,maxlen);
istrstream strin(s);
while(sin>>x) cout<<x<<endl;

#include<stdlib.h>
#include<time.h>

int main()
{
srand(time(NULL));
....
....
// rand()%n can get a integer from 0..(n-1)
....
}

I am very sorry to do that ......

Some graph problems can be easily solved by DFS.
Backtracking is a kind of method to tranverse a search tree.
Diffient problems diffient methods.
If you want to know more, just visit the following site,
you will get reply very soon.( A lot of excellent programmers from China there)

Welcome to visit ...

It is suggested that before you code you must think carefully about the time complexity. Some program seems unable to brute force or prune,so there maybe a dynamic programming algorithm or other simple algoritm. Practice more, learn more.

If you want to know more, just visit the following site,
you ...

the forum can be viewed now,
but there is a lot of bugs now.
You can try to ask problems there,
I think some excellent students will answer your question!

Olympiad in Informatics player -> OIer
ACM ICPC palyer -> ICPCer


PS: the forum has terminated for some technology reason,
please visit it after I notice you again!

http://www.ioiforum.org/en/

The forum is for internationl discuss!

These days are for test only.

After final publish, there will be many strong OIer / ICPCer there!