《Java语言程序设计(基础篇)》(第10版 梁勇 著)第十九章练习题答案

Java语言程序设计（基础篇）》（第10版梁勇著）第十九章练习题答案19.1classGenericStack<E>{publicfinalstaticintINITIAL_SIZE=16;privateE[]elements;privateintsize;/**Constructastackwiththedefaultinitialcapacity*/publicGenericStack(){this(INITIAL_SIZE);}/**Constructastackwiththespecifiedinitialcapacity*/publicGenericStack(intinitialCapacity){elements=(E[])newObject[initialCapacity];}/**Pushanewelementintothetopofthestack*/publicEpush(Evalue){if(size>=elements.length){E[]temp=(E[])newObject[elements.length*2];System.arraycopy(elements,0,temp,0,elements.length);elements=temp;}returnelements[size++]=value;}/**Returnandremovethetopelementfromthestack*/publicEpop(){returnelements[--size];}/**Returnthetopelementfromthestack*/publicEpeek(){returnelements[size-1];}/**Exercise03_21whetherthestackisempty*/publicbooleanisEmpty(){returnsize==0;}/**Returnthenumberofelementsinthestack*/publicintgetSize(){returnsize;}}19.2publicclassExercise19_02{publicstaticvoidmain(String[]args){GenericStack<String>stack=newGenericStack<String>();stack.push("Tom");stack.push("George");stack.push("Peter");System.out.println(stack.getSize());System.out.println(stack.peek());System.out.println(stack.pop());System.out.println(stack.peek());}//GenericStack.java:ImplementingastackusinginheritancestaticclassGenericStack<E>extendsjava.util.ArrayList<E>{publicbooleanisEmpty(){returnsuper.isEmpty();}publicintgetSize(){returnsize();}publicObjectpeek(){returnget(getSize()-1);}publicObjectpop(){Objecto=get(getSize()-1);remove(getSize()-1);returno;}publicObjectpush(Eo){add(o);returno;}publicintsearch(Objecto){returnindexOf(o);}@OverridepublicStringtoString(){return"stack:"+toString();}}}19.3importjava.util.ArrayList;publicclassExercise19_03{publicstaticvoidmain(String[]args){ArrayList<Integer>list=newArrayList<Integer>();list.add(14);list.add(24);list.add(14);list.add(42);list.add(25);ArrayList<Integer>newList=removeDuplicates(list);System.out.print(newList);}publicstatic<E>ArrayList<E>removeDuplicates(ArrayList<E>list){ArrayList<E>result=newArrayList<E>();for(Ee:list){if(!result.contains(e))result.add(e);}returnresult;}}19.4publicclassExercise19_04{publicstatic<EextendsComparable<E>>voidselectionSort(E[]list){for(inti=1;i<list.length;i++){/**insertlist[i]intoasortedsublistlist[0..i-1]sothatlist[0..i]issorted.*/EcurrentElement=list[i];intk;for(k=i-1;k>=0&&list[k].compareTo(currentElement)>0;k--){list[k+1]=list[k];}//Insertthecurrentelementintolist[k+1]list[k+1]=currentElement;}}}19.5publicclassExercise19_05{publicstaticvoidmain(String[]args){Integer[]numbers={1,2,3};System.out.println(max(numbers));String[]words={"red","green","blue"};System.out.println(max(words));Circle[]circles={newCircle(3),newCircle(2.9),newCircle(5.9)};System.out.println(max(circles));}staticclassCircleimplementsComparable<Circle>{doubleradius;publicCircle(doubleradius){this.radius=radius;}@OverridepublicintcompareTo(Circlec){if(radius<c.radius)}}}return-1;elseif(radius==c.radius)return0;elsereturn1;}@OverridepublicStringtoString(){return"Circleradius:"+radius;}}publicstatic<EextendsComparable<E>>Emax(E[]list){Emax=list[0];for(inti=1;i<list.length;i++){if(pareTo(list[i])<0){max=list[i];}}returnmax;}}19.6publicclassExercise19_06{publicstaticvoidmain(String[]args){Integer[][]numbers={{1,2,3},{4,4,6}};System.out.println(max(numbers));}publicstatic<EextendsComparable<E>>Emax(E[][]list){Emax=list[0][0];for(inti=1;i<list.length;i++){for(intj=1;j<list[i].length;j++){if(pareTo(list[i][j])<0){max=list[i][j];returnmax;}}19.7publicclassExercise19_07{/**Usebinarysearchtofindthekeyinthelist*/publicstatic<EextendsComparable<E>>intbinarySearch(E[]list,Ekey){intlow=0;inthigh=list.length-1;while(high>=low){intmid=(low+high)/2;if(pareTo(list[mid])<0){high=mid-1;}elseif(key.equals(list[mid])){returnmid;}else{low=mid+1;}}return-low-1;//Nowhigh<low}}19.8importjava.util.ArrayList;publicclassExercise19_08{publicstaticvoidmain(String[]args){ArrayList<Integer>list=newArrayList<Integer>();list.add(14);list.add(24);list.add(4);list.add(42);list.add(5);shuffle(list);for(inti=0;i<list.size();i++)System.out.print(list.get(i)+"");}publicstatic<E>voidshuffle(ArrayList<E>list){for(inti=0;i<list.size()-1;i++){intindex=(int)(Math.random()*list.size());Etemp=list.get(i);list.set(i,list.get(index));list.set(index,temp);}}}19.9importjava.util.ArrayList;publicclassExercise19_09{publicstaticvoidmain(String[]args){ArrayList<Integer>list=newArrayList<Integer>();list.add(14);list.add(24);list.add(4);list.add(42);list.add(5);Exercise19_09.<Integer>sort(list);System.out.print(list);}/**Sortanarrayofcomparableobjects*/publicstatic<EextendsComparable<E>>voidsort(ArrayList<E>list){EcurrentMin;intcurrentMinIndex;for(inti=0;i<list.size()-1;i++){//Findtheminimuminthelist[i+1..list.length-2]currentMin=list.get(i);currentMinIndex=i;for(intj=i+1;j<list.size();j++){if(currentMpareTo(list.get(j))>0){currentMin=list.get(j);currentMinIndex=j;}}//Swaplist[i]withlist[currentMinIndex]ifnecessary;if(currentMinIndex!=i){list.set(currentMinIndex,list.get(i));list.set(i,currentMin);}}}}19.10importjava.util.ArrayList;publicclassExercise19_10{publicstaticvoidmain(String[]args){ArrayList<Integer>list=newArrayList<Integer>();list.add(14);list.add(24);list.add(4);list.add(42);list.add(5);System.out.print(max(list));}publicstatic<EextendsComparable<E>>Emax(ArrayList<E>list){EcurrentMax=list.get(0);for(inti=1;i<list.size();i++)if(currentMpareTo(list.get(i))<0)currentMax=list.get(i);returncurrentMax;}}19.11importjava.util.ArrayList;publicclassExercise19_11{publicstaticvoidmain(String[]args){//CreatetwoComplexarraysm1andm2Complex[][]m1=newComplex[3][3];Complex[][]m2=newComplex[3][3];for(inti=0;i<m1.length;i++)for(intj=0;j<m1[0].length;j++){m1[i][j]=newComplex(i+1,j+5);m2[i][j]=newComplex(i+1,j+6);}//CreateaninstanceofComplexMatrixComplexMatrixrationalMatrix=newComplexMatrix();System.out.println("\nm1+m2is");GenericMatrix.printResult(m1,m2,rationalMatrix.addMatrix(m1,m2),'+');System.out.println("\nm1*m2is");GenericMatrix.printResult(m1,m2,rationalMatrix.multiplyMatrix(m1,m2),'*');}publicstatic<E>ArrayList<E>removeDuplicates(ArrayList<E>list){ArrayList<E>result=newArrayList<E>();for(Ee:list){if(!result.contains(e))result.add(e);}returnresult;}}classComplexMatrixextendsGenericMatrix<Complex>{@Override/**Addtworationalnumbers*/protectedComplexadd(Complexr1,Complexr2){returnr1.add(r2);}@Override/**Multiplytworationalnumbers*/protectedComplexmultiply(Complexr1,Complexr2){returnr1.multiply(r2);}@Override/**SpecifyzeroforaComplexnumber*/protectedComplexzero(){returnnewComplex(0,0);}}abstractclassGenericMatrix<E>{/**Abstractmethodforaddingtwoelementsofthematrices*/protectedabstractEadd(Eo1,Eo2);/**Abstractmethodformultiplyingtwoelementsofthematrices*/protectedabstractEmultiply(Eo1,Eo2);/**Abstractmethodfordefiningzeroforthematrixelement*/protectedabstractEzero();/**Addtwomatrices*/publicE[][]addMatrix(E[][]matrix1,E[][]matrix2){//Checkboundsofthetwomatricesif((matrix1.length!=matrix2.length)||(matrix1[0].length!=matrix2[0].length)){thrownewRuntimeException("Thematricesdonothavethesamesize");}E[][]result=(E[][])newObject[matrix1.length][matrix1[0].length];//Performadditionfor(inti=0;i<result.length;i++)for(intj=0;j<result[i].length;j++){result[i][j]=add(matrix1[i][j],matrix2[i][j]);}returnresult;}/**Multiplytwomatrices*/publicE[][]multiplyMatrix(E[][]matrix1,E[][]matrix2){//Checkboundsif(matrix1[0].length!=matrix2.length){thrownewRuntimeException("Thematricesdonothavecompatiblesize");}//CreateresultmatrixE[][]result=(E[][])newObject[matrix1.length][matrix2[0].length];/