Can someone please point out what is wrong in my solution. It is giving WA for 3 testcases. I have used a simple binary search with a check function. The bounds are 0 and 2e18 and I am including Ci + D as shoot time also. Please help me out ! Thank you !

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We are binary searching over double here, so it is always a good idea to either run binary search for a fixed number of iterations(say 100) and change the condition as while(high -low >= eps) where eps is 1e-10.
The second way to do this is to binary search over the integer part of the answer and then manually check for the decimal upto 6 places. This is what I had done. You can check out my solution here.

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Can you please provide the code of 1st approach that gives AC.

Hey ! Thanks for your reply. I tried implementing the first approach you mentioned but it still isn’t working. Can you point out the mistake ?

You need not update ans at each iteration. the final answer will be lo only. Also, i fixed the number of iterations without bothering the second condition of the difference of hi and lo. Also, try after using setprecision.

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I made a few changes to your code. This is like the standard way to implement binary search on doubles. Hope you get it now.


Look at these. Very helpful. This type of problems are quite standard in binary search and the technique is quite well explained here.

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Thanks a lot !.. I tweaked my original code and just put a setprecision(10) while ouputting the answer and it worked.


I did quite similar, getting wrong answer on internal test cases. Can you help?

Just changed one line :
maxNum = max(maxNum+mid, a[i] + mid);

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Thank you very much.