CodeForces Tester giving wrong output



I just began giving competitions on codeforces . However when I coded one of the questions the judge show that for a particular test case my program was giving WA . When I reviewed that test case and ran it on ideone it gave the correct expected output . What could be the problem ?

Link to my code (with the specific test case) :

Link to the problem :


You forget to initialize local variable total.

Some clang static analizer output:

B.cpp:42:60: warning: The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage
  for (int c(0);c < n;c++){int a;sd(a);arr.push_back(a);total+=a;}

Also in case of such undefined behavior issue this link could be useful.