View Compilation Error

0_0_38773272_9399.cpp:7:1: error: 'vector' does not name a type
    7 | vector<int>b[50005];
      | ^~~~~~
0_0_38773272_9399.cpp: In function 'int main()':
0_0_38773272_9399.cpp:26:28: error: 'b' was not declared in this scope
   26 |     for(int i=1;i<=cnt;i++)b[e[i].w].push_back(i);
      |                            ^
0_0_38773272_9399.cpp:28:21: error: 'b' was not declared in this scope
   28 |       for(int j=0;j<b[i].size();j++){
      |                     ^
0_0_38773272_9399.cpp:30:16: error: 'f2' was not declared in this scope; did you mean 'f1'?
   30 |         if(f1!=f2)f[f1]=f2,ans+=i;
      |                ^~
      |                f1
0_0_38773272_9399.cpp:34:26: error: 'b' was not declared in this scope
   34 |     for(int i=1;i<=n;i++)b[i].clear();
      |                          ^