Can anyone explain to me why the BFS algorithm finds the shortest distance from u to v ? i understand but i am unable toexplain it, i think i don't understand it enough.. :( ( my writing is bad sorry)

Hi can you explain me how Chinese student are trained at school because i think teachers' level in China can not catch up with their student.

I have trouble in concentrating when i study for example checking my message and listening to music . What you do to keep your concentration ? ;(

I need help with dynamic programming SOS

"This afternoon, I read a blog about Dominator069. He reached Master in only 4 months and International Grandmaster in 1 year. As far as I know, he already had great mathematical skills before he started CP. Do you think learning math first or solving more problems is better?"

Do you know the youngest Grandmaster 0_0

When i look at Chinese contestant in this year IOI , i am nearly depressed ... According to a blog on cf i read , they wrote that a Chinese contestant had reached LGM when he was in grade 9th LOL . Do you know their learning method to reach that level :((>?

What math level do i need for taking part in IOI ? and how to reach that level pls

I have trouble in solving problems on codeforce . Can u tell me how to train my mathematical skill pls;((