View Compilation Error

0_0_38219443_15924.cpp: In function 'void solve()':
0_0_38219443_15924.cpp:52:8: error: expected unqualified-id before '[' token
   auto [w, x, y] = *st.begin();
        ^
0_0_38219443_15924.cpp:54:3: error: 'x' was not declared in this scope
   x = find(x), y = find(y);
   ^
0_0_38219443_15924.cpp:54:16: error: 'y' was not declared in this scope
   x = find(x), y = find(y);
                ^
0_0_38219443_15924.cpp:56:10: error: 'w' was not declared in this scope
   ans += w;
          ^