I encountered the following issue with C++14. It seems that it is much slower than C++ and C++11. Here the same code submitted with C++, C++11, C++14.

• C++ 29189853 405 ms in test case 8
• C++11 29189812 436 ms in test case 8
• C++14 29189820 > 1000 ms in test case 8

The issue is not related to I/O (so cin/cout slowness addressed here is not involved), since the program has only to read 2 integers and write 1 integer. Moreover the code doesn't use any exotic structure or library, but only vectors.

What is the cause of this issue? Is it a known problem of the compiler?