reverse sort

Vedha does not like to sort an $array$ in normal ways. Now she has chosen a way to sort by reversing some of the subarrays of the given array. She added a rule i.e, to only reverse the subarrays which have its sum of elements at most $Y$. Later her friend notices that it is not always possible to do so by the rules done by Vedha. Help Vedha to find whether a given $Array$ can be sorted by the a