whydoesthiscodegiveanegativehashcode？
import java.util.HashSet；
import java.util.Set；
公共类ab {
//*
字符串单身网络args )。
string S1=' operationsonadynamicsetcanbegroupedintotwocategoriesqueries，whichsimplyreturninformationabouttheset，and modifynamichet whichchangetheset.hereisalistoftypicaloperationspecificapplicationwillusuallyrequireonlyafewofthesetobeimplementedsomed thekeysaredrawnfromatotallyordere，such as the real numbers， orthesetofallwordsundertheusualalphabeticordering.atotalorderingallowsustodefinetheminimumelementoftheset，for example， ortospeakofthenextelementlargerthanagivenelementinaset.operationsondynamicsetcanbegroupedintotwocatected
String s2='abc '；
}
}
thestringclassoverrideshashcode (toproducedeterministicresults.theresulthasnothingtodowithmemoryaddreses.the string.he she
thehashcodeforastringobjectiscomputedas
s [0] * 31 ^ [ n-1 ] S1 * 31 ^ [ n-2 ] . s [ n-1 ]
using int arithmetic，wheres [ I ] istheithcharacterofthestring，n is the length of the string，and^Indicatesexponentiation.(
notethatforevenrelativelyshortstringsthevaluecangettoobigforaninteger.duringthecalculations，wheneveranoverflowocursonlythythettttheger
At the end of the calculation，ifthemostsignificantbitoftheresultingintegerissettheintegerisnegative，if not then positive。