Can someone please tell me where I am wrong . Here is my

```
[1]. I maintained 2 segment trees for maximum query and for sum query and then I found lower bound of prefix sum for the interval where my sum/2 lies . Please someone reply :( what is the error in my code
[1]: https://www.codechef.com/viewsolution/18887866
```

The problem is in your (sum/2) thingâ€¦see this testcase->

1

2 1

3 4

1 1 2

Now when you run this testcase, your code will give 2 as output which is correct but when you see your median, it shows 1 which is wrongâ€¦So what i want to say is that for this testcase your answer is right but your median is wrongâ€¦the wrong calculation of median leads to WA in some other testcase.

The problem is in (sum/2) as i saidâ€¦in this testcase sum is 7 so sum/2=3â€¦now you are searching for 3 whereas the median element is 4(middle element) . Since first element is 3 your code displays index 1(1-based) as median whereas median is 2.

So simply replace your (sum/2) by (sum+1/2)â€¦if sum will be even then both will be same but if sum is odd, they will differ and hence the median.

I did this change to your code and got AC.

Hope this helps!!

4 Likes

Holy Moly.

Thanks a lot man , it helped me for sure.Silly mistake during contest cost me a question

Thanks again for helping me out.

@swapnil159 thanks a lot dude. I made the same mistake.

its okk guysâ€¦took me 3 hours to figure out this in my code.

1 Like

can someone help me please? Here is my

```
(https://www.codechef.com/viewsolution/18902163). I know its lengthy. but just tell me the test case where it fails please.
```

Thank You very much @swapnil159 , This comment could have saved my whole day. I was doing the same mistake (sum)/2 thing instead of (sum+1)/2 . Thank you