View Compilation Error

0_0_36134557_14037.cpp: In function 'int main()':
0_0_36134557_14037.cpp:76:16: error: expected unqualified-id before '[' token
           auto [x, y] = t.second;
                ^
0_0_36134557_14037.cpp:77:14: error: 'x' was not declared in this scope
           mx[x].insert(y);
              ^
0_0_36134557_14037.cpp:77:24: error: 'y' was not declared in this scope
           mx[x].insert(y);
                        ^