OJ Board

I was using union-find algorithm at the contest. But I got several WA's. I think my program failed in handling reversible connection (i.e. 1->2 and 2->1).


i use union-find algorithm , and i got WA too . i think this algorithm is correct , but why i got wrong ?

That's because union-find is for ...

You should set edge to 0. Your code fails when the first tree (only) can talk to a doctor.

How?? What you have changed in the code?

used the union find algorithm.

Thank u guys for ur help. I was giving up this problem but I got it ACed finally

but sometimes you can take more egdes not only those needed to form spanning tree

I couldn't get what u mean

yup right. stupid mistake
Thnx very much, got it Aced now

What's wrong with this:
it gave me WA

Thnx andmej for the proof. I've been so stupid sorry :$

& I read jvimal post again and got it

Thnx all

Got it ACed but not convinced. Do u have some kind of proof or something ??!!

Actually I tried to think of an O(1) algo to solve this problem using just math & just couldn't find any.

I have 2 unknown variables & I need 2 equations to determine them while I only have that g * l = a * b.
So :D ??!!

I also know that
a % g = 0
& b % g = 0
& l % a = 0
& l % b = 0
but these ...

I'm trying to solve this problem but got WA

I'm using 2 nested loops for a & b, both loops starts from g & ends at l. I did some analysis & figured out that a & b must be in this interval [g, l]. the steps of the 2 loops is also g since I don't need to examine numbers that's not divisable by g. So ...

Hey guy,

I'm really getting frustrated by this problem :S, I don't know what's wrong. I've passed all 153 test cases posted CDiMa & still getting WA. I don't know what's wrong


struct Graph
{
int nVertices;
int nEdges;
int edges[100][100];
int degree[100];
}
g;

map<int, int>mp;
bool arr[100 ...

There is something I really miss in the old system which is viewing other people's accepted problems. I'm now coaching a group of student in my college & need to see who solved what problems.

Thnx in advance

hey guys,

This problem is driving me crazy :S.
First I got it WA several times. Then I changed the way I read input from reading with cin.getline to reading a character by a character for cases where 2 test share a line.
Then I got TLE for that. I changed my code to sum the tree nodes while ...

Thnx Mostafa but I'm still getting WA :S. I don't know what's wrong with my code. The array size is 1500. Is it big enough ??!!
It's a simple BFS problem. I've used the same BFS function before and got some ACs with it.
Is there any trick about this problem ??!!