背包问题，单元最短路径等贪心算法c++源码

#include <iostream> using namespace std; #define Bsize 3 #define Psize 20 struct pageInfor { int content;//页面号 int timer;//被访问标记 }; class PRA { public: PRA(void); int findSpace(void);//查找是否有空闲内存 int findExist(int curpage);//查找内存中是否有该页面 int findReplace(void);//查找应予置换的页面 void display(void);//显示 void FIFO(void);//FIFO算法 void LRU(void);//LRU算法 void Optimal(void);//OPTIMAL算法 void BlockClear(void);//BLOCK恢复 pageInfor * block;//物理块 pageInfor * page;//页面号串 private: }; PRA::PRA(void) { int QString[20]={7,0,1,2,0,3,0,4,2,3,0,3,2,1,2,0,1,7,0,1}; int i = 0; block = new pageInfor[Bsize]; for(int i=0; i<Bsize; i++) { block[i].content = -1; block[i].timer = 0; } page = new pageInfor[Psize]; for(i=0; i<Psize; i++) { page[i].content = QString[i]; page[i].timer = 0; } } int PRA::findSpace(void) { for(int i=0; i<Bsize; i++) if(block[i].content == -1) return i;//找到空闲内存，返回BLOCK中位置 return -1; } int PRA::findExist(int curpage) { for(int i=0; i<Bsize; i++) if(block[i].content == page[curpage].content) return i;//找到内存中有该页面，返回BLOCK中位置 return -1; } int PRA::findReplace(void) { int pos = 0; for(int i=0; i<Bsize; i++) if(block[i].timer >= block[pos].timer) pos = i;//找到应予置换页面，返回BLOCK中位置 return pos; } void PRA::display(void) { for(int i=0; i<Bsize; i++) if(block[i].content != -1) cout<<block[i].content<<" "; cout<<endl; } void PRA::Optimal(void) { int exist,space,position ; for(int i=0; i<Psize; i++) { exist = findExist(i); if(exist != -1) { cout<<"不缺页"<<endl; } else { space = findSpace(); if(space != -1) { block[space] = page[i]; display(); } else { for(int k=0; k<Bsize; k++) for(int j=i; j<Psize; j++) { if(block[k].content != page[j].content) { block[k].timer = 1000; }//将来不会用，设置TIMER为一个很大数 else { block[k].timer = j; break; } } position = findReplace(); block[position] = page[i]; display(); } } } } void PRA::LRU(void) { int exist,space,position ; for(int i=0; i<Psize; i++) { exist = findExist(i); if(exist != -1) { cout<<"不缺页"<<endl; block[exist].timer = -1;//恢复存在的并刚访问过的BLOCK中页面TIMER为-1 } else { space = findSpace(); if(space != -1) { block[space] = page[i]; display(); } else { position = findReplace(); block[position] = page[i]; display(); } } for(int j=0; j<Bsize; j++) block[j].timer++; } } void PRA::FIFO(void) { int exist,space,position ; for(int i=0; i<Psize; i++) { exist = findExist(i); if(exist != -1) {cout<<"不缺页"<<endl;} else { space = findSpace(); if(space != -1) { block[space] = page[i]; display(); } else { position = findReplace(); block[position] = page[i]; display(); } } for(int j=0; j<Bsize; j++) block[j].timer++;//BLOCK中所有页面TIMER++ } } void PRA::BlockClear(void) { for(int i=0; i<Bsize; i++) { block[i].content = -1; block[i].timer = 0; } } void main(void) { cout<<"|----------页 面 置 换算法----------|"<<endl; cout<<"|---power by zhanjiantao(028054115)---|"<<endl; cout<<"|-------------------------------------|"<<endl; cout<<"页面号引用串:7,0,1,2,0,3,0,4,2,3,0,3,2,1,2,0,1,7,0,1"<<endl; cout<<"----------------------------------------------------"<<endl; cout<<"选择<1>应用Optimal算法"<<endl; cout<<"选择<2>应用FIFO算法"<<endl; cout<<"选择<3>应用LRU算法"<<endl; cout<<"选择<0>退出"<<endl; int select; PRA test; while(select) { cin>>select; switch(select) { case 0: break; case 1: cout<<"Optimal算法结果如下:"<<endl; test.Optimal(); test.BlockClear(); cout<<"----------------------"<<endl; break; case 2: cout<<"FIFO算法结果如下:"<<endl; test.FIFO(); test.BlockClear(); cout<<"----------------------"<<endl; break; case 3: cout<<"LRU算法结果如下:"<<endl; test.LRU(); test.BlockClear(); cout<<"----------------------"<<endl; break; default: cout<<"请输入正确功能号"<<endl; break; } } }