View Compilation Error

0_0_19837361_4120.cpp: In function 'bool check()':
0_0_19837361_4120.cpp:45:6: error: redefinition of 'bool check()'
 bool check(){
      ^
0_0_19837361_4120.cpp:31:6: note: 'bool check()' previously defined here
 bool check(){
      ^
0_0_19837361_4120.cpp: In function 'void bfs()':
0_0_19837361_4120.cpp:78:51: error: 'sort' was not declared in this scope
                     sort(he.us.begin(),he.us.end());
                                                   ^