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Can you tell me the numbers of some graph problems ?
Thank you in advance

I am not going to prove you why my solution is right. This is a very popular game called Nim. Lets say we have n stones a1, a2, ... , an
If, and only if, a1 xor a2 xor ... xor an = 0 =) 'NO'
a1 xor a2 xor ... xor an <> 0 =) 'YES'

Can someone give me some sites which are hosting online contests. I want real time practise

Has someone tried to make a good algorithms for playing the game "Clickomania". I'm opened for idias.

Can someone tell me the ID's of some game problems. My search rate is very slow

I know it can be solved with greedy. But I want to solve it with this theorem very very much And the only greedy I know works in
O(n.m).

I don't uderstand why I have WA. I use Erdos and Gallai (1960) theorem. At first I check if the sum is odd, if there is element bigger than n or if there is a negative element.
Than I sort the degree sequence and used two index trees to implement Erdos and Gallai (1960) theorem. Help me please :( Or ...