/in/foo.cc: In function 'bool dfs(int, int, int, int)':
/in/foo.cc:22:6: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
      for(int i=1;i<=n;i++)
      ^~~
/in/foo.cc:28:7: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
       dfs(k+1,len-a[flag],tot-a[flag],flag+1);
       ^~~
/in/foo.cc:31:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^