/in/foo.cc: In function 'int dfs(int, int)':
/in/foo.cc:26:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(u==n||!res) return res; int flowout=0,v,f;
  ^~
/in/foo.cc:26:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  if(u==n||!res) return res; int flowout=0,v,f;
                             ^~~
/in/foo.cc: In function 'int dinic()':
/in/foo.cc:38:9: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return ans;
         ^~~