Upsolve the problems after the contest and practice those topics which you feel u r weak at.

When will the editorial be published?

ashish1610 u hacked two div1A problem just 2-3 seconds before I could hack it.

I have implemented what has been mentioned in the editorial but it is giving wrong answer on test case #6.

Solution Link http://ideone.com/SS4RAe

Where am I going wrong?

Great tutorial!! PrinceOfPersia can u write a blog on BIT? That would be a lot of help!!

In 'three sorted arrays' binary search solution : Is the value of t1=[2 1 0] correct? Also while calculating answer 'ans = t1[1]+t1[2]+t1[2] = 3+3+1' why are we doing this?

Can anyone explain the dynamic programming solution of problem E?

Here is the ideone link of the solution http://ideone.com/oGmWhE

both one

Solution to problem 4 was dp + dfs.

Here is mine accepted solution of it in codeforces gym. http://codeforces.me/gym/100579/submission/9474632

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What is the meaning of shortest path in this question?

Good tutorial

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If I want to find distinct increasing subsequence as in this question http://www.spoj.com/problems/INCDSEQ/

what modification I need to make in the above code?

Merry Christmas to everyone !! Became expert !!

great explanation !!! thanks..

can any anyone explain how is the following relation F(i)=prod(F(j)+1) true? where F(i) be the number of valid sets contain node i as root. F(j) is a node in subtree of i.

Saratov is beautiful !!

It was a great contest!!

7 2 1 answer-3

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Why don't we divide by the factorial instead of calculating inverse and multiply ? int ans = (f[n] * 1LL / f[k]) % mod; ans = (ans * 1LL /f[n — k]) % mod;

(E) part int modpow(int a, int b){ int ans = 1; while(b){ if(b & 1) ans = (ans * li(a)) % mod; a = (a * li(a)) % mod; b >>= 1; } return ans; } int rev(int v){ return modpow(v, mod — 2); } Why are we using (mod-2) ? thanks in advance