BZOJ 5441 [Ceoi2018]Cloud computing

题目链接

https://www.lydsy.com/JudgeOnline/problem.php?id=5441

题解

按照频率排序后转化成背包问题。

代码

#include 
#include 
#include 

int read()
{
  int x=0,f=1;
  char ch=getchar();
  while((ch<'0')||(ch>'9'))
    {
      if(ch=='-')
        {
          f=-f;
        }
      ch=getchar();
    }
  while((ch>='0')&&(ch<='9'))
    {
      x=x*10+ch-'0';
      ch=getchar();
    }
  return x*f;
}

const int maxn=2000;
const int maxm=50;

struct query
{
  int c,f,v;

  bool operator <(const query &other) const
  {
    if(f==other.f)
      {
        return vreturn f>other.f;
  }
};

long long f[maxn*maxm+10],ans;
int n,m,tot;
query q[maxn*2+10];

int main()
{
  n=read();
  for(int i=1; i<=n; ++i)
    {
      q[i].c=read();
      q[i].f=read();
      q[i].v=-read();
    }
  m=read();
  for(int i=1; i<=m; ++i)
    {
      q[n+i].c=-read();
      q[n+i].f=read();
      q[n+i].v=read();
    }
  std::sort(q+1,q+n+m+1);
  memset(f,-63,sizeof f);
  f[0]=0;
  for(int i=1; i<=n+m; ++i)
    {
      if(q[i].c>0)
        {
          for(int j=tot; j>=0; --j)
            {
              f[j+q[i].c]=std::max(f[j+q[i].c],f[j]+q[i].v);
            }
          tot+=q[i].c;
        }
      else
        {
          for(int j=0; j-q[i].c<=tot; ++j)
            {
              f[j]=std::max(f[j],f[j-q[i].c]+q[i].v);
            }
        }
    }
  for(int i=0; i<=tot; ++i)
    {
      ans=std::max(ans,f[i]);
    }
  printf("%lld\n",ans);
  return 0;
}

转载于:https://www.cnblogs.com/Canopus-wym/p/10376143.html