What is wrong with my code for long challenge problem Appy and Balloons?



Problem Link

Previous solution link

My above solution is running for some cases i.e., it was partially accepted , I made a small change in the code in Line 54:
temp+=(Math.ceil( ((float) (C*-mid))/(float)B*));

changed to


After doing this I got AC for all cases

New solution link

Please can anyone tell me why is this happening


In C/C++ , ceil() uses “double” type as its argument and returns “double” as well.Here, the value which is the argument of ceil() (c*-mid) can be as large as 10^18 which exceeds the range of “double”. Hence,ceil() returns unexpected value and you got WA for large numbers (The case is same in Java)


I tried it for 10^18 in c++ it’s returning
1e+09 when i use ceil
and 1000000000 when i am using other approach


Can you share your code?

#include <bits/stdc++.h>
using namespace std;

int main()


long double c=1000000000000000000.76;

cout << ceil(c) <<endl;


This won’t output 1000000000000000001. Instead will output 1000000000000000000 (1e+18)

PS: Don’t trust floating point numbers. They can’t be stored/represented accurately and they betray when you need them the most :confused: