src.cpp: In function 'void bfs()':
src.cpp:18:8: error: 'v' was not declared in this scope
ch[v]=1;
^
src.cpp: In function 'int main()':
src.cpp:39:43: error: statement cannot resolve address of overloaded function
ios_base:: sync_with_stdio(0); cin.tie; cout.tie(0);
^