View Compilation Error

0_0_38440956_23046.cpp: In function 'void solve()':
0_0_38440956_23046.cpp:32:14: error: expected unqualified-id before '[' token
         auto [u, v, w] = num[i];
              ^
0_0_38440956_23046.cpp:33:18: error: 'w' was not declared in this scope
         if (!vis[w])
                  ^
0_0_38440956_23046.cpp:34:23: error: 'u' was not declared in this scope
             ans += (s[u] ^ s[v]).count();
                       ^
0_0_38440956_23046.cpp:34:30: error: 'v' was not declared in this scope
             ans += (s[u] ^ s[v]).count();
                              ^
0_0_38440956_23046.cpp:35:11: error: 'u' was not declared in this scope
         s[u][v] = s[v][u] = 1;
           ^
0_0_38440956_23046.cpp:35:14: error: 'v' was not declared in this scope
         s[u][v] = s[v][u] = 1;
              ^