01背包之广度搜索

#include <stdio.h>#include <iostream>#include <stdlib.h>#include <fstream>#include "vector"#include "queue"using namespace std;#define N 500struct Bag{    int id;    int w;    int v;    double wv;    /*friend booloperator< (Bag a, Bag b)    {        return a.wv > b.wv; //结构体中，x小的优先级高    }*/};struct node{    double weight;    double value;    double uprofit;    int level;    friend bool operator < (node a, node b)    {        return a.uprofit < b.uprofit;      //结构体中，x小的优先级高    }};priority_queue<node> Q;int C,n;double best,Wsum,Vsum;struct Bag bag[N];//struct node a[]int tempans[N],ans[N];int cmp(const void *a,const void *b){    struct Bag *c = (Bag *) a;    struct Bag *d = (Bag *) b;    return c->wv<d->wv?1:-1;};double shangjie(int x){    double tmp = Vsum;    double left = C-Wsum;    while(x<n&&bag[x].w<=left)    {        tmp+=bag[x].v;        left-=bag[x].w;        x++;    }    if(x<n)    {        tmp+=left*bag[x].wv;    }    return tmp;}void addnode(double up,double cv,double cw,int level){    struct node s;    s.uprofit = up;    s.value = cv;    s.weight = cw;    s.level = level;    Q.push(s);    return ;}int cv = 0, cw = 0;int main(){    freopen("d:/2.in","r",stdin);    scanf("%d %d",&C,&n);    best = 0;    Wsum=0;    Vsum=0;    memset(ans,0,sizeof(ans));    memset(tempans,0,sizeof(tempans));    int tempV= 0, tempW =0;//物品的全部重量与全部价值    for(int i = 0; i<n; i++)    {        scanf("%d %d",&bag[i].w,&bag[i].v);        bag[i].id=i;        bag[i].wv = bag[i].v*1.0/bag[i].w;        //printf("%d %d\n",bag[i].w,bag[i].v);        tempV += bag[i].v;        tempW += bag[i].w;    }   /*    double up = 100;    for(int i=1;i<=10;i++)    {     addnode(up,Vsum,Wsum,i+1);     Vsum ++;     Wsum ++;     if(Vsum>5)     up = up*2;     else     up = up - 10;    }    for(int i = 1;i<=10;i++)    {        printf("%lf %lf %lf %d\n",Q.top().uprofit,Q.top().value,Q.top().weight,Q.top().level);        Q.pop();    }    */    if(tempV<=C)   //如果全部重量小于能承载的重量 那么全选    {        printf("%d\n",tempW);        for(int i = 0; i<n; i++)            printf("%d 1\n",i+1);        return 0;    }    qsort(bag,n,sizeof(bag[0]),cmp); //按单位重量的价排序值    int i = 0;    Vsum = 0;    Wsum = 0;    double up=shangjie(0);//价值上界    while(i!=n)    {  //cout<<"i="<<i<<endl;        if(Wsum+bag[i].w<=C)        {            if(Vsum+bag[i].v>best)                best = Vsum+bag[i].v;               // cout<<"--"<<Vsum+bag[i].v<<"best"<<best<<endl;            addnode(up,Vsum+bag[i].v,Wsum+bag[i].w,i+1);        }        up = shangjie(i+1);        if(up>best)        addnode(up,Vsum,Wsum,i+1);        //node tmp;        if(!Q.empty()){        Wsum = Q.top().weight;        Vsum = Q.top().value;        up = Q.top().uprofit;        i=Q.top().level;        Q.pop();        }        else        {           break;        }    }   printf("answer = %.0lf\n",best);    return 0;}