hdu 4296 (成都赛区2012网络赛)

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>

using namespace std;

#define maxn 100005

struct blo
{
int w;
int d;
}block[maxn];

bool cmp(const blo&a,const blo&b)
{
return a.w+a.d<b.w+b.d;
}

int main()
{
int n;
while(scanf("%d",&n) != EOF)
{
for(int i=0;i<n;i++)
scanf("%d%d",&block[i].w,&block[i].d);
sort(block,block+n,cmp);
__int64 sum=block[0].w;
__int64 ans=0;
for(int i=1;i<n;i++)
{
__int64 tmp = sum - block[i].d;
if(tmp>ans)
ans=tmp;
sum+=block[i].w;
}
printf("%I64d\n",ans);
}
return 0;

}