/in/foo.cc: In function 'int read()':
/in/foo.cc:12:9: warning: variable 'sgn' set but not used [-Wunused-but-set-variable]
 int x=0,sgn=1;char ch=getchar();
         ^~~
/in/foo.cc: In function 'bool check(int)':
/in/foo.cc:53:1: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
 if (maxo-cut<=mid) return true;return false;
 ^~
/in/foo.cc:53:32: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
 if (maxo-cut<=mid) return true;return false;
                                ^~~~~~