HDU 4296 Buildings

按si+wi的和排序贪心即可

#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstdio>
#define LL __int64
using namespace std;
const int maxn=100001;
struct node
{
    LL w;
    LL s;
}p[maxn];
bool cmp(const node a, const node b)
{
    return a.w+a.s<b.w+b.s;
}
int main()
{
    int i,n;
    LL max,a,b;
    while(~scanf("%d",&n))
    {
        for(i=0;i<n;i++)
            scanf("%I64d%I64d",&p[i].w,&p[i].s);
        sort(p,p+n,cmp);
        a=p[0].w;
        max=-p[0].s;
        for(i=1;i<n;i++)
        {
            b=a-p[i].s;
            a+=p[i].w;
            if(b>max) 
                max=b;
        }
        if(max<0) 
            puts("0");
        else 
            printf("%I64d\n",max);
    }
    return 0;
}