Daily Diary (Competitive Coding in Summers)

Revision en11, by satylogin, 2017-05-25 07:31:25

I realised that there is only one way improve one's skill, and that is through practice. So I decided to practice more topics and more problems on codeforces and different judges. This is simply a daily record for what I did through my vacation.

I also want to tell you about stopstalk.com . It is a good site to make and keep you daily coding record.

16 MAY 2017

Problems Solved -
1. http://codeforces.me/problemset/problem/535/D
This was a simple problem and it used Z function for prefix length calculation
solution linkhttp://codeforces.me/contest/535/submission/27152004
2. http://codeforces.me/problemset/problem/551/B
Although the problem was simple, I had some trouble in understanding the language of the problem. It took time more than required.
solution linkhttp://codeforces.me/contest/551/submission/27160921


Participated Contest -

I participated in a virtual contest ( Round 308 DIV 2 ). I was able to solve all the problems, but then last problem was accepted just 2 min before the contest ended.

A. http://codeforces.me/problemset/problem/552/A
The problem was fairly simple, but then rather than simply adding the area, I made a 2-D hash map. Guess I have to practice a little more for problem A.
solution linkhttp://codeforces.me/contest/552/submission/27165795
B. http://codeforces.me/problemset/problem/552/B
The problem was mathematical. I solved it by forming a series. Got one WA for not using long long.
solution linkhttp://codeforces.me/contest/552/submission/27165912
C. http://codeforces.me/problemset/problem/552/C
I solved the problem using meet in middle. But the editorial talked about an another wonderful way to solve that. Do watch the editorial solution. It is an excellent concept in itself.
solution linkhttp://codeforces.me/contest/552/submission/27166275
D. http://codeforces.me/problemset/problem/552/D
This was another interesting problem to solve. I used concept of slopes to generate triangle. Got 4 WA. Was not taking care of slope sign and was not handling 0 slope and inf slope cases.
solution linkhttp://codeforces.me/contest/552/submission/27166893
E. http://codeforces.me/problemset/problem/552/E
Pretty interesting problem to solve both by greedy and by DP. I used the later N*N approach. Initially thought of using multiplication as boundaries, but then didn't wanted to take risk. Got 4 WA because of simple mistakes in the loops. Got accepted just before 2 min from end.
solution linkhttp://codeforces.me/contest/552/submission/27167519

17 MAY 2017

Solved very few problems. Found a lot of problems hard to solve.

Problems Solved -
1. http://codeforces.me/problemset/problem/551/C
It was a good problem of binary search. Although I found it a little hard for problem C Div 2. Guess I have practice still more. It used an standard NlogN solution using binary search where we have to binary search over the completion time of the task and then check the users required. Good problem for practice.
solution link — http://codeforces.me/contest/551/submission/27175198
2. http://codeforces.me/problemset/problem/549/A
Fairly easy problem. Requires direct implementation
solution link — http://codeforces.me/contest/549/submission/27181042
3. http://codeforces.me/problemset/problem/534/E
very good problem for practice. I was missing a lot of corner cases while solving. Had to search for a method to find mismatch in logN time in the array. I think this problem was worth solving.
solution link — http://codeforces.me/contest/534/submission/27184116
Problems Unsolved -
1. http://codeforces.me/problemset/problem/534/F
2. http://codeforces.me/contest/549/problem/H
It would be a great help if someone could help me with the unsolved problems.

18 MAY 2017

Problems Solved -

I solved some simple problems on hackerearth and URI. One problem that I liked was from URI —

1. https://www.urionlinejudge.com.br/judge/en/problems/view/1469
This was a good problem where we had to swap nodes. I used map for mapping and index function and an inverse index function for getting position of a node and getting value at any position. for swapping, I swapped those two.
solution link — https://code.hackerearth.com/a4c9b2Y

Then some problems on codeforces

1. http://codeforces.me/problemset/problem/549/H
Finally solved the matrix problem. Used binary search for reducing the size of squares.
solution link — http://codeforces.me/contest/549/submission/27189164
2. http://codeforces.me/problemset/problem/519/A
Direct implementation
solution link — http://codeforces.me/contest/519/submission/27193319
3. http://codeforces.me/problemset/problem/519/B
Direct implementation
solution link — http://codeforces.me/contest/519/submission/27201264
4. http://codeforces.me/problemset/problem/519/C
Turned out to be easy for problem C. Just travel over one possible value, then find the value of other and then maximise the sum.
solution link — http://codeforces.me/contest/519/submission/27201384
5. http://codeforces.me/problemset/problem/519/D
Had fun while solving this. Used map to store pairs of character and prefix sum values. Then used a linear algorithm to add values for all location while deleting previously occurred nodes. Did in NlogN.
solution link — http://codeforces.me/contest/519/submission/27202224
Problems unsolved -
1. http://codeforces.me/problemset/problem/519/E

19 MAY 2017

I only participated in a virtual contest on URI. Few of the good problems were —

1. https://www.urionlinejudge.com.br/judge/en/problems/view/2049
Hint
2. https://www.urionlinejudge.com.br/judge/en/problems/view/1923
Hint
3. https://www.urionlinejudge.com.br/judge/en/problems/view/1580
Hint

20 MAY 2017

Today I solved problems on snackdown qualifiers and hackerearth circuits. In night, I participated in round 415 DIV 2. The results were not very good. Was only able to solve 3 problems. I feel like I have difficulty with interactive problems. Will have to practice more.

Apart from the contests, I solved an extra problem on hackerrank.

  1. https://www.hackerrank.com/challenges/kth-ancestor
Hint

21 MAY 2017

Today I practise some problems on codeforces and spoj.

1. http://www.spoj.com/problems/LCA/
Hint
2. http://codeforces.me/problemset/problem/192/E
Hint
3. http://codeforces.me/problemset/problem/556/A
Hint
4. http://codeforces.me/problemset/problem/556/B
Hint
5. http://codeforces.me/problemset/problem/556/C
Hint
6. http://codeforces.me/problemset/problem/556/D
Hint

22 MAY 2017

Today was an extremely bad day for me. I participated in a virtual contest and was able to solve only 2 problems. Realised how bad I am at geometry. So tomorrow is going to be an extensive practice session. I also solved one problem on hackerearth circuits. A bad day :(

23 MAY 2017

Today I solved a few problems and participated in a virtual contest. Guess something went wrong with CF. In the middle of virtual contest, It dumped me out of the contest, and when 45 min were left, It again brought back me in. I solved One problem on hackerearth circuits.

solved problems
1. http://codeforces.me/problemset/problem/471/A
Hint
2. http://codeforces.me/problemset/problem/471/B
Hint
3. http://codeforces.me/problemset/problem/471/C
Hint
4. http://www.codeforces.com/problemset/problem/471/D
Hint
5. http://codeforces.me/problemset/problem/208/E
Hint
6. https://www.hackerrank.com/challenges/inverse-rmq
Hint

24 MAY 2017

Still doing hackerearth circuits. Unable to do consecutive remainder. Still have to practice more maths.

History

 
 
 
 
Revisions
 
 
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en23 English satylogin 2017-06-12 12:02:00 969
en22 English satylogin 2017-06-09 10:18:55 1307 Tiny change: 'n###### 1.http://cod' -> 'n###### 1. http://cod'
en21 English satylogin 2017-06-06 08:48:57 709
en20 English satylogin 2017-06-03 21:23:27 1185
en19 English satylogin 2017-06-02 21:04:12 949
en18 English satylogin 2017-05-31 19:36:34 1125
en17 English satylogin 2017-05-30 20:26:54 2883
en16 English satylogin 2017-05-29 16:59:46 1192
en15 English satylogin 2017-05-28 14:55:26 1801
en14 English satylogin 2017-05-27 08:30:54 7 Tiny change: 'r>\n\n## 25 MAY 2017\' -> 'r>\n\n## 26 MAY 2017\'
en13 English satylogin 2017-05-27 08:30:17 925
en12 English satylogin 2017-05-26 05:14:51 2081
en11 English satylogin 2017-05-25 07:31:25 131
en10 English satylogin 2017-05-24 08:48:14 2279 Tiny change: '>\n\n##### 5. h' -> '>\n\n###### 5. h'
en9 English satylogin 2017-05-23 07:48:10 298
en8 English satylogin 2017-05-22 08:26:38 3083
en7 English satylogin 2017-05-21 08:57:38 937
en6 English satylogin 2017-05-20 10:22:41 1031 Tiny change: 'eddc17Y\n<spoiler>' -> 'eddc17Y\n</spoiler>'
en5 English satylogin 2017-05-19 07:56:54 1865 Tiny change: 'ved - \n\n1. http://' -> 'ved - \n\n###### 1. http://'
en4 English satylogin 2017-05-18 04:50:02 1357
en3 English satylogin 2017-05-17 11:28:10 5 Tiny change: 'you about stopstalk.com. It is a ' -> 'you about **stopstalk.com** . It is a '
en2 English satylogin 2017-05-17 10:51:46 0 (published)
en1 English satylogin 2017-05-17 10:51:06 2862 Initial revision (saved to drafts)