chokudai's blog

By chokudai, history, 4 weeks ago,

We will hold AtCoder Beginner Contest 220.

The point values will be 100-200-300-400-500-500-600-600.

We are looking forward to your participation!

• +45

 » 4 weeks ago, # |   -59 This contest clashes with a codechef contest, can it be postponed/preponed to remove the clash ?
 » 4 weeks ago, # |   +61 Wtf is F, did you guys run out of problems?
•  » » 4 weeks ago, # ^ |   0 yep , simple f, i do f in 5 minutes and still strugling on e
 » 4 weeks ago, # |   0 I was $3^{rd}$ at the 10-15 minute mark in the leaderboard cuz of F lol. Used the exact same code for Tree Distances II CSES just changing " " to "\n"...
 » 4 weeks ago, # |   +39 F is the reason that you should read all the problems
 » 4 weeks ago, # |   0 How can I say, I solved F but didn't solve E before the end of the contest...
 » 4 weeks ago, # | ← Rev. 2 →   0 why is this DP solution wrong for problem D? My Approach: dp[i][j] = no. of ways to get j at i-th index after doing some operations. and let's assume instead of popping two elements and then pushing, we reach at an index i doing such operations and all the prev indices are processed, so final ans will be to find the no. of ways at last index. to get j at ith index, our ans will only depend on no. of ways to get 'x' at index i-1 such that (v[i]+x)%10 == j or (v[i]*x)%10 == j and no other values than x should affect no. of ways to get j at ith index. so summation of the no. of ways of to get each such x should get the no. of ways to get j at ith index.
•  » » 4 weeks ago, # ^ | ← Rev. 2 →   0 When you are incrementing dp[i][j], you have to add dp[i-1][last] twice in case both the conditions are satisfied.
•  » » » 4 weeks ago, # ^ |   0 thanks i totally missed that. it works now.
 » 4 weeks ago, # |   0 How do I increase my speed? I solved 4 problems and my rank is 2245. XYZ solved 4 problems and rank is 1578.
 » 4 weeks ago, # |   0 Can someone provide tags for all the problems?
 » 4 weeks ago, # |   +10 Well, at least F has a different output format. https://cses.fi/problemset/task/1133
•  » » 4 weeks ago, # ^ |   +3 ok fine change ' ' to '\n' PS: It works on CSES with '\n' as the separator anyway so you can submit the Atcoder submission exactly to CSES and it'll AC.
 » 4 weeks ago, # |   0 Did anyone else also just look at F and open CSES on the next click?
 » 4 weeks ago, # |   0 the bonus task of F: 791D - Bear and Tree Jumps
 » 4 weeks ago, # |   0 can anyone share his recursive approach for problem d.
•  » » 4 weeks ago, # ^ |   0 at any state ,we are possible two move,we should go both move and calculate the total value. here my submission, if you are any query ask me ..https://atcoder.jp/contests/abc220/submissions/26150901
•  » » » 4 weeks ago, # ^ |   0 thanks . i got your soln but how can we do it in one pass.
•  » » » » 4 weeks ago, # ^ | ← Rev. 2 →   0 it's dp.when one valid move are finished ,you must hit to the base case. you remember that ,you will be hit in the base case many more times ,also hit to the same state more times. so you must memorize to the state value.
 » 3 weeks ago, # |   0 How would a Top-Down solution look like for abc220_d? Problem Link: https://atcoder.jp/contests/abc220/tasks/abc220_d Their official editorial has a bottom-up solution. I have understood and solved it with the bottom-up approach. I was just curious how would top solution will look like for this problem? I tried, but there seems that I have to invert the modulo operator in here to get to the top-down solution. the DP states and the base case look intuitive, the DP call is not so much.
•  » » 3 weeks ago, # ^ |   0