Hello CF community I have been doing cp for 3 years,I solved more than 1341 problems ,but I'm still specialist,I'm really frustrated and I feel that I'm mentally retarted,many of my friends who started with me at the same time are masters and candidates now. Every time I fall down,I summon my strength and fight again,every 10 days I create a marathon on vjudge containings problems with specific difficulty(current one is 2200) and solve them.

I solved many problems ,and tried many strategies:solving easy problems,hard problems,virtual participation and upsolving but all this hard work was in vain .I'm not smart like others but I'm proud of being a hard worker . So guys you have the statement,any accepted solution please! (sorry for the very poor english)

Hello CF community,While solving problem D New Year and Conferencefrom contest Hello 2020 ,I got runtime error in test 8 I tried some tests and I figured out that for some cases the problem is with my struct (some variables in my struct are huge random numbers and I cannot sort my vector of this struct while I'm sure that I'm setting every variable) here is link for my submission any help would be appreciated,and thanks

Hello everyone ! I'm fourth year software engineering student.I've been doing CP for three years .I learned many algorithms and I solved many problems but the problem is that I cannot do my best during contests for that I'm going to set myself a 30 day challenge :making virtual participation every day in a contest and upsolve all unsolved problems. so if any one remember a good round (quality of problems,gap of difficulty between problems)please share it with me. I'll update the blog every day to post my rating in the contest and let's see if this challenge gonna make me a junior tourist ^__^.

first contest:round 422 rank:1368

second contest: round 480 rank:1058

third contest: round 353 rank:1398

fourth contest:educational 80 rank:2045

5th contest: round 464 rank:308 (best rank I ever achieved ^___^)

6th contest: round 489 rank :269 :my best rank so far :)

7th contest : educational 42 rank:1002 :(

8th contest: round 476 rank:1449 :(

9th contest: round 614 rank: 1526 :(

10th contest: round 345 rank:331

11th contest: global round 5 rank:2323

12th contest: round 410 rank: 361 :)

13th contest :global round 4 rank : 2071 ;(

14th contest: round 616 rank : 1514

15th contest : round 511 rank : 373

Note:I'm not counting csacademy Vc's ^__^

Hello community! I'm wondering how to solve 381E:Sereja and Brackets but instead of searching the maximum correct bracket subsequence I'm looking for maximum correct bracket substring! any help would be appreciated and thanks^__^

How long have you been coding? and how do you train ? Sharing is caring^__^

Hello coders! let's suppose we have three numbers n,k,mod=1e9+7 where n,k<=1e9 how to calculate nCk %mod! any hint please! Thanks^__^

Hello coders, I'm wondering how to find all edges in a graph which if removed, would disconnect a specific pair of vertices? any hint and Thanks^__^

Hello codeforces community! I'm stuck in this problem :you are given two strings s1 and s2 in one operation ou can reverse a substring in s2 what's the minimum number of operations needed to get identical strings.Opertations are made only on string 2? link Bonus:what's would be the answer if we can apply operations on both strings? any help! and Thanks^__^

Hello I'm stuck in this problem: you are given a maze of size n*m (n,m<=1000),every cell has a number written on it and you need to go from cell (0,0) to cell(n-1,m-1) with minimum cost. you can move up,down,left,right .if you want to go to cell (x,y) and the number in this cell is different from number of current one then cost is increased otherwise cost is unchanged. link any help ! and Thanks

Hello! There is a field n×m, and k of its cells are impassable walls. A robot is initially at the cell (1,1) (bottom left). The robot can only move right or up, and eventually it needs to get into the cell (n,m), avoiding all obstacles. You need to count the number of ways he can do it. Assume that the sizes n and m are very large (say, 109), and the number k is small (around 100) how to solve that in o(k^3)? any hint please and thanks!

Hello I'm trying to solve this question using Aho-corasick tree:how to Find the lexicographically smallest string of a given length that doesn't match any given strings !I'm stuck and I cannot implement that :( any help will be appreciated ^__^ and Thanks!

Hello ! I'm stuck in this interesting problem I'm writing this because I didn't find the editorial (english version) Any help! Thanks