foo.cc:32:11: error: expected identifier before '(' token
   32 | void union(int a,int b){
      |           ^
foo.cc:32:12: error: expected unqualified-id before 'int'
   32 | void union(int a,int b){
      |            ^~~
foo.cc:32:12: error: expected ')' before 'int'
   32 | void union(int a,int b){
      |           ~^~~
      |            )
foo.cc: In function 'int main()':
foo.cc:58:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Node>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |   while(k<a.size()&&a[k].h>b[i].h){
      |         ~^~~~~~~~~
foo.cc:65:18: error: expected primary-expression before 'union'
   65 |      if(vis[id2])union(id1,id2);
      |                  ^~~~~

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