/in/foo.cc:13:30: warning: '-std=c++11' is not an option that controls warnings [-Wpragmas]
 #pragma GCC diagnostic error "-std=c++11"
                              ^~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:75:17: error: 'ed' was not declared in this scope
    int hNum=sum[ed]-sum[st-1],jNum=len-hNum;
                 ^~
/in/foo.cc:76:11: error: 'jNum' was not declared in this scope
    if(abs(jNum-hNum)<=d||jNum==len||hNum==len)
           ^~~~