View Compilation Error

0_0_38207057_28580.cpp: In function 'void solve()':
0_0_38207057_28580.cpp:91:8: error: expected unqualified-id before '[' token
   auto [u, tp] = stk.back(); stk.pop_back();
        ^
0_0_38207057_28580.cpp:92:6: error: 'tp' was not declared in this scope
   if(tp == 0) {
      ^
0_0_38207057_28580.cpp:93:7: error: 'u' was not declared in this scope
    he(u);
       ^
0_0_38207057_28580.cpp:97:7: error: 'u' was not declared in this scope
    be(u);
       ^