There was a problem in Google APAC Test 2016 Round C (Problem B) — gFiles (https://code.google.com/codejam/contest/4284487/dashboard#s=p1 — Google Login may be required).

The approach that I came up with which ran successfully on the sample cases was:

Find the lower bound and upper bound on the number of elements (because for a particular value of k[i] and p[i] only a handful of values of total files are possible which lie between lower_bound and upper_bound).

To find these bound, iterate over the entry i (p[i] and k[i]) and do

Iterate over array

if(p[i] != 0 && k[i] != 0)

lower_bound = max(lower_bound, ceil((k[i]*100.0)/(p[i]+0.9999999)) upper_bound = min(upper_bound, floor((k[i]*100.0)/(p[i]))

else if(p[i] == 0 && k[i] != 0)

lower_bound = max(lower_bound, ceil((k[i]*100.0)/(p[i]+0.9999999))

End of Iteration

If lower_bound == upper_bound

answer = lower_bound

else

answer = -1

While giving the correct outputs for the sample cases, it failed on system test on small inputs.

Can anyone give a hint on where was the fault in my approach ?