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It_Wasnt_Me's blog

By It_Wasnt_Me, 2 months ago, ,

https://codeforces.com/contest/195/problem/D I am so close to the solution but there is something that confuse me

the problem describe that $S(x)$ is sum of $n$ functions, the solution just use $F(x)$ for each line,

Should I consider $S(x)$ so I should sum all $k_i$ and $b_i$ ? https://codeforces.com/contest/195/submission/67170155 Anyone know why I am wrong?

Can anyone help me If he have explanation for the solution or explain the tutorial more because it is a bit unclear for me. :)

• +3

By It_Wasnt_Me, history, 4 months ago, ,

552D - Vanya and Triangles in this problem, shortly you should count all number of triangles with non-zero area.

My idea was to count all triangle I could which is NC3 then I will subtract zero-area triangles

zero-area triangle will occur if there is 3 points on the same line(horizontal, vertical) or have same diagonal.

Unfortunately I received (Wrong answer) and I can't prove why my solution is wrong, I tested it on several testcases and it gives Right answer.

https://ideone.com/iiuxuP Any help