It happened during last Div.4
In this submission in compilation log you can see only warnings, no errors, but verdict is CE
So experimentally I figured out that an error in line 1285, ofc locally it works good with C++17:
constexpr auto darr = array<pair<int, int>, 4>{{{1, 0}, {0, 1}, {-1, 0}, {0, -1}}};
Will be nice if codeforces show full compilation log or somehow print errors first
Auto comment: topic has been updated by elseecay (previous revision, new revision, compare).
Have you considered fixing the warnings to see the error?