https://www.codechef.com/viewsolution/27402788

shows WA

custom input shows correct answer

help plz

# S10E - Editorial

I’ve just done a seat-of-the-pants implementation of this plus a testcase generator, and it looks like your solution fails on the following testcase:

```
1
9
690 570 470 385 712 710 391 584 579
```

Edit:

Diagnostics:

```
Day: 1 out of 9 Good
Day: 2 out of 9 Good
Day: 3 out of 9 Good
Day: 4 out of 9 Good
Day: 5 out of 9 Not good - price is 385 on day 4 which is <= 712
Day: 6 out of 9 Not good - price is 385 on day 4 which is <= 710
Day: 7 out of 9 Not good - price is 385 on day 4 which is <= 391
Day: 8 out of 9 Not good - price is 391 on day 7 which is <= 584
Day: 9 out of 9 Not good - price is 391 on day 7 which is <= 579
4
```

thank u so much!

i’ll check it again

Yours seems to fail on:

```
1
8
399 411 491 621 745 602 482 537
```

This is what I get (I’ve added some diagnostics to my code to explain what’s going on):

```
Day: 1 out of 8 Good
Day: 2 out of 8 Not good - price is 399 on day 1 which is <= 411
Day: 3 out of 8 Not good - price is 411 on day 2 which is <= 491
Day: 4 out of 8 Not good - price is 491 on day 3 which is <= 621
Day: 5 out of 8 Not good - price is 621 on day 4 which is <= 745
Day: 6 out of 8 Not good - price is 491 on day 3 which is <= 602
Day: 7 out of 8 Not good - price is 411 on day 2 which is <= 482
Day: 8 out of 8 Not good - price is 482 on day 7 which is <= 537
1
```

https://www.codechef.com/viewsolution/27403656

thank u! managed to give a correct solution

used your testcase to find an error in my code

Take a look at the breakdown of my BACREP submission, here:

https://www.codechef.com/viewsolution/27345547

There are 16 “Tasks”. Each “Task” is a test input file which is provided to your program as input when your submission is evaluated. These Tasks are grouped into subtasks - for example, the Tasks/ test input files 0, 1, 2 3 and 12 are all grouped into Subtask #1.

Let’s see what the constraints section says about Subtask #1:

**Subtask #1 (20 points):** 1 \le N,Q \le 5000

That means that the test input in each of the Tasks 0, 1, 2, 3 and 12 are *guaranteed* to have N \le 5000 and Q \le 5000 - this means that a naive O(N \times Q) solution will likely satisfy this Subtask (i.e. will successfully pass Tasks 0, 1, 2 ,3 and 12), and so get at least 20 of the possible 100 points.

Can’t understand why my program is giving me the wrong answer, I have tested the program with some of the custom inputs mentioned in the comments but its still not working https://www.codechef.com/viewsolution/27403916. If somebody can please hep me understand where I am getting it wrong

Consider the testcase:

```
1
9
468 463 701 508 670 638 463 394 402
```

My results (with Diagnostic info):

```
Day: 1 out of 9 Good
Day: 2 out of 9 Good
Day: 3 out of 9 Not good - price is 463 on day 2 which is <= 701
Day: 4 out of 9 Not good - price is 463 on day 2 which is <= 508
Day: 5 out of 9 Not good - price is 508 on day 4 which is <= 670
Day: 6 out of 9 Not good - price is 508 on day 4 which is <= 638
Day: 7 out of 9 Not good - price is 463 on day 2 which is <= 463
Day: 8 out of 9 Good
Day: 9 out of 9 Not good - price is 394 on day 8 which is <= 402
3
```

Yours seems to fail on the following testcase:

```
1
8
675 499 431 629 611 412 420 389
```

My solution (with extra diagnostic output added) gives:

```
Day: 1 out of 8 Good
Day: 2 out of 8 Good
Day: 3 out of 8 Good
Day: 4 out of 8 Not good - price is 431 on day 3 which is <= 629
Day: 5 out of 8 Not good - price is 431 on day 3 which is <= 611
Day: 6 out of 8 Good
Day: 7 out of 8 Not good - price is 412 on day 6 which is <= 420
Day: 8 out of 8 Good
5
```

Thanks buddy!

what is your thought process behind this solution? i can’t understand ,please explain!

Your logic seems OK (well - it seems to give the correct answers, at least XD), but read the “Output” section of the question carefully

Tiny mistake Consider the testcase:

```
2
7
375 750 723 662 647 656 619
7
375 750 723 662 647 656 619
```