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ID：13404704
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页数：4页
时间：2018-07-22
《回溯算法之01背包问题java源程序》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。
1、实验报告11课程数据结构与算法实验名称回溯法第页班级11计本学号105032011130姓名风律澈实验日期：2013年5月20日报告退发(订正、重做)一、实验目的掌握回溯法的原理和应用。二、实验环境1、微型计算机一台2、WINDOWS操作系统，JavaSDK，Eclipse开发环境三、实验内容必做题：1、编写程序，实现n后问题算法。（如果上周没完成，这周完成）2、编写程序，采用回溯法实现0-1背包问题。四、实验步骤和结果(附上代码和程序运行结果截图)2、0-1回溯背包问题importjava.util.ArrayList;importjava.util.PriorityQueue;pub
2、licclassmain{/***@paramargs*/publicstaticvoidmain(String[]args){//TODOAuto-generatedmethodstu//初始化工作baga=newbag(7);ArrayListobjects=newArrayList();PriorityQueuepq=newPriorityQueue();intv[]={9,10,7,4};intw[]={3,5,2,1};for(inti=0;i3、,w[i]));objects.add(newobject(v[i],w[i]));}//生成单位价值排序数组，将物品以单位价值从高到低排列，记录数组intvw[]=newint[v.length];for(inti=0;iobjects,baga){//TODOAuto-gen4、eratedmethodstubif(i>objects.size())//叶子{a.setmaxvaule(a.getvalue());return;}if(a.getcontain()+objects.get(i-1).getweight()<=a.getmaxweight()){a.addobject(objects.get(i-1));backtrack(i+1,objects,a);a.removeobjec(objects.get(i-1));}if(bound(i+1,objects,a)>a.getmaxvalue()){backtrack(i+1,objects,a);5、}}privatestaticintbound(inti,ArrayListobjects,baga){//TODOAuto-generatedmethodstubintleftcontain=a.getmaxweight()-a.getcontain();intbound=a.getvalue();while((i<=objects.size())&&(objects.get(i-1).getweight()<=leftcontain)){leftcontain-=objects.get(i-1).getweight();bound+=objects.get(i-1).6、getvalue();i++;}if(i<=objects.size())bound+=objects.get(i-1).getvalue()*leftcontain/objects.get(i-1).getweight();returnbound;}}importjava.util.ArrayList;publicclassbag{privateintcontain;privateintvalue;privateintmaxweight;privateintmaxvalue;privateArrayListobjects;publicbag(intmaxw){this.7、contain=0;this.value=0;this.maxweight=maxw;this.maxvalue=0;this.objects=newArrayList();}publicintgetcontain(){returncontain;}publicvoidresetcontain(intc){this.contain=c;}publicintgetvalue(){returnvalue;};public
3、,w[i]));objects.add(newobject(v[i],w[i]));}//生成单位价值排序数组，将物品以单位价值从高到低排列，记录数组intvw[]=newint[v.length];for(inti=0;iobjects,baga){//TODOAuto-gen
4、eratedmethodstubif(i>objects.size())//叶子{a.setmaxvaule(a.getvalue());return;}if(a.getcontain()+objects.get(i-1).getweight()<=a.getmaxweight()){a.addobject(objects.get(i-1));backtrack(i+1,objects,a);a.removeobjec(objects.get(i-1));}if(bound(i+1,objects,a)>a.getmaxvalue()){backtrack(i+1,objects,a);
5、}}privatestaticintbound(inti,ArrayListobjects,baga){//TODOAuto-generatedmethodstubintleftcontain=a.getmaxweight()-a.getcontain();intbound=a.getvalue();while((i<=objects.size())&&(objects.get(i-1).getweight()<=leftcontain)){leftcontain-=objects.get(i-1).getweight();bound+=objects.get(i-1).
6、getvalue();i++;}if(i<=objects.size())bound+=objects.get(i-1).getvalue()*leftcontain/objects.get(i-1).getweight();returnbound;}}importjava.util.ArrayList;publicclassbag{privateintcontain;privateintvalue;privateintmaxweight;privateintmaxvalue;privateArrayListobjects;publicbag(intmaxw){this.
7、contain=0;this.value=0;this.maxweight=maxw;this.maxvalue=0;this.objects=newArrayList();}publicintgetcontain(){returncontain;}publicvoidresetcontain(intc){this.contain=c;}publicintgetvalue(){returnvalue;};public
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