11052 - Economic phone calls

[Adrian Kuegel]

Yes, you are right, the sample input is not in the judge test cases, I forgot to include it.

[joeluchoa]

I've got WA!
Somebory can give me a hint?

This is my code:

Code: Select all

Removed, I had not understood the problem correctly!

[fh]

I used backtracking to consider all possibilities... I'm also curious whether it can be solved using greedy?

[Martin Macko]

I've got WA!
Somebory can give me a hint?

Not working for:

Code: Select all

4
04:09:06:59 47 -
02:07:05:49 47 +
09:01:03:11 47 -
01:30:02:34 47 -
0

The correct output is:

Code: Select all

2

[joeluchoa]

I'm not understand the above input!!
Why is 2 the output?
You can explain to me?

I think that the answer would be:
3

4
04:09:06:59 47 - [year 2]
02:07:05:49 47 + [year 1]
09:01:03:11 47 - <delete>
01:30:02:34 47 - [year 0 (current)]

What is wrong in my idea?

[Martin Macko]

I'm not understand the above input!!
Why is 2 the output?
You can explain to me?
What is wrong in my idea?

The years of all the phone calls are as follows:

Code: Select all

04:09:06:59 47 -     [year 1] (as 04>02)
02:07:05:49 47 +     [year 1] (as 02<09)
09:01:03:11 47 -     [year 0] (as 09>01)
01:30:02:34 47 -     [year 0] (as it is the first one)

After removing the first and the last one you get:

Code: Select all

04:09:06:59 47 -     [delete]
02:07:05:49 47 +     [year 1] (as 02<09)
09:01:03:11 47 -     [year 0] (as it is the first one)
01:30:02:34 47 -     [delete]

[joeluchoa]

Thanks Martin Macko. I hadn't undestood the problem correctly!

[Towhid]

I used backtracking to consider all possibilities... I'm also curious whether it can be solved using greedy?

I have used Greedy approach. The code is a bit big with some if else condition. I started from the first entry....

[lonelyone]

I'm not understand the above input!!
Why is 2 the output?
You can explain to me?
What is wrong in my idea?

The years of all the phone calls are as follows:

Code: Select all

04:09:06:59 47 -     [year 1] (as 04>02)
02:07:05:49 47 +     [year 1] (as 02<09)
09:01:03:11 47 -     [year 0] (as 09>01)
01:30:02:34 47 -     [year 0] (as it is the first one)

After removing the first and the last one you get:

Code: Select all

04:09:06:59 47 -     [delete]
02:07:05:49 47 +     [year 1] (as 02<09)
09:01:03:11 47 -     [year 0] (as it is the first one)
01:30:02:34 47 -     [delete]

Sorry, I still couldn't understand it.
Could someone explain it more detailed?

[sakhassan]

Can any one pls clearly explain when should I delete a log ???? & why ?
I didnt clearly understand the problem

Thanks in Advance

[annhy]

The years of all the phone calls are as follows:

Code: Select all

04:09:06:59 47 -     [year 1] (as 04>02)
02:07:05:49 47 +     [year 1] (as 02<09)
09:01:03:11 47 -     [year 0] (as 09>01)
01:30:02:34 47 -     [year 0] (as it is the first one)

After removing the first and the last one you get:

Code: Select all

04:09:06:59 47 -     [delete]
02:07:05:49 47 +     [year 1] (as 02<09)
09:01:03:11 47 -     [year 0] (as it is the first one)
01:30:02:34 47 -     [delete]

Strangely, my understanding is different to yours, but I get AC..

In my understanding, the years of all the phone calls are as follows:

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04:09:06:59 47 -     [year -2]
02:07:05:49 47 +     [year -1]
09:01:03:11 47 -     [year -1] (the last year)
01:30:02:34 47 -     [year 0] (current year) 

The result:

Code: Select all

04:09:06:59 47 -     [delete]  (before the first important call)
02:07:05:49 47 +     [year -1]
09:01:03:11 47 -     [delete]  (02 > 01, this one can be deleted)
01:30:02:34 47 -     [year 0]

[dibery]

One more case.

Input:

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9              
09:16:10:18 0 -
01:12:03:22 0 +
02:22:14:48 0 -
04:05:11:29 0 +
03:04:01:42 0 +
05:10:08:08 0 -
12:18:02:27 0 -
05:01:08:27 0 -
09:08:04:31 0 +
0

Output:

Code: Select all

5