View Compilation Error

0_0_39837643_5876.cpp: In function 'int find_set(int)':
0_0_39837643_5876.cpp:8:15: error: 'root' was not declared in this scope
    8 |     return x==root[x]?x:find_set(root[x]);
      |               ^~~~
0_0_39837643_5876.cpp: In function 'void merge_set(int, int)':
0_0_39837643_5876.cpp:14:14: error: 'root' was not declared in this scope
   14 |     if(i!=j) root[j] = i;
      |              ^~~~