Invitation to CodeChef May Lunchtime 2019 sponsored by ShareChat!

Greetings Codechef community!

CodeChef’s May Lunchtime sponsored by ShareChat is just around the corner and you are all invited to participate. This is not only an opportunity to get some practice and improve your coding skills, but also a chance to improve your rating!

Team CodeChef is also seeking problem ideas for our upcoming contests! If you think you have an idea that will make for an exciting contest problem, then send it to us using this form: Come and take your first step towards becoming a CodeChef problem setter!

ShareChat - India’s fastest growing social network is inviting participants of the Lunchtime to come apply for exciting work opportunities. Job opportunities are open to programmers across the world and internship opportunities are exclusively aimed at final year B.Tech students who have already been placed and looking forward to gaining startup experience. Visit the contest page for more details.

I hope you will join your fellow programmers and enjoy the contest problems. Joining me on the problem setting panel are:

Contest Details:

  • Start Date & Time: 25th May 2019 (1930 hrs) to 25th May 2019 (2230 hrs). (Indian Standard Time — +5:30 GMT) — Check your timezone

  • Contest link:

  • Registration: You just need to have a CodeChef handle to participate. For all those, who are interested and do not have a CodeChef handle, are requested to register in order to participate.

  • Prizes: Top 10 Indian and top 10 Global school students from ranklist will receive certificates and CodeChef laddus, with which the winners can claim cool CodeChef goodies. Know more here: How do I win a CodeChef Goodie?.

(For those who have not yet got their previous winning, please send an email to

Good Luck!

Hope to see you participating!!

Happy Programming!!

UPD: The editorials of first 4 problems are ready and will be posted soon. The editorials of other 3 problems will be posted tomorrow. Meanwhile, you can go through the Author’s notes for those problems here


Contest is very nice, but problems didn’t load,same problem with rank-list and submissions :slight_smile:

I Think the test case of problem ABDTOLL are very weak. My O(N2) solution get accepted. Please add some more test case for practice

Can someone find why is this code for ABDTOLL getting WA.

Code Link You can compare it with my AC code.

Your code fails for this test case

9 1 10
4 8 9 12 14 7 6 5 2
1 2
1 3
2 4
2 5
3 6
6 7
7 8
7 9

While adding the reduced_cost you did not took into consideration the toll cost which was already paid. So the fix would be “reduced_cost+=cost[s] - x” , instead of “reduced_cost+=x”.


1 Like

@aman_robotics Can you give a small testcase, I am finding hard to get the bug intuitively.Or can you elaborate more.

Editorials for all problems have been posted. Feel free to have a look!


why its not in here

how people will find it later

would you moved editorials to that page too plz