<JZOJ1286>太空电梯

一道简单可爱的dp

#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#define max(a,b) (a>b?a:b)
#define rint register int
using std::sort;
using std::cout;
using std::endl;
template <class T>inline void read(T &X)
{
    X=;int W=;char ch=;
    while(!isdigit(ch))W|=ch=='-',ch=getchar();
    while(isdigit(ch))X=(X<<)+(X<<)+(ch^),ch=getchar();
    X=W?-X:X;return;
}

int n,dp[]={},ans=;
struct node{int h,a,c;}e[];
int cmp(node x,node y){return x.a<y.a;}
int main()
{
    read(n);
    for(rint i=;i<=n;++i)read(e[i].h),read(e[i].a),read(e[i].c);
    sort(e+,e+n+,cmp);

    dp[]=;
    for(rint i=;i<=n;++i)
    {
        for(rint j=e[i].a;j>=;--j)
        {
            if(dp[j])
            {
                for(rint k=;k<=e[i].c;++k)
                {
                    if(j+k*e[i].h>e[i].a)break;
                    dp[j+k*e[i].h]=;
                }
            }
        }
    }
    for(rint i=e[n].a;i>=;--i)
        if(dp[i]){printf("%d\n",i);break;}
return ;
}