算法设计的背包问题-------------用贪心算法求解

 

•public static float knapsack(float c,float [] w, float [] v,float [] x)

•   {

•      int n=v.length;

•      Element [] d = new Element [n];

•      for (int i = 0; i < n; i++) d[i] = new Element(w[i],v[i],i);

•      MergeSort.mergeSort(d);    / /按单位价值由高道低排序

•      int i;

•      float opt=0;

•      for (i=0;i<n;i++) x[i]=0;

•      for (i=0;i<n;i++) {

•        if (d[i].w>c) break;

•        x[d[i].i]=1;   / /标记i的物品已被装入背包

•        opt+=d[i].v;

•        c-=d[i].w;

•        }

•      if (i<n){

•        x[d[i].i]=c/d[i].w;

•        opt+=x[d[i].i]*d[i].v;

•        }   / /把背包装满

•      return opt;

•   }