hdu 4296（buildings）

题目链接：点击打开链接

题目分析：贪心算法+轮换对称 ，a：wi，si；b:wj，sj；

对于a在b上：pda：wi-sj

        b在a上：wj-si；

当a优于b时;wi-sj>wj-si    wi+si>wj+wj

    #include<cstdio>    #include<cstdlib>    #include<algorithm>    #include<algorithm>    using namespace std;    struct data{     int weight;     int strenth;    };    data info[100010];    int cmp( data a,data b)    {        return (a.weight+a.strenth)<(b.weight+b.strenth);    }    int main()    {        int n,i,w,s;        __int64 ans,temp,sum;        while(scanf("%d",&n)!=EOF)        {            for(i=0;i<n;i++)            scanf("%d %d",&info[i].weight,&info[i].strenth);            sort(info,info+n,cmp);            ans=info[0].weight-info[1].strenth;            sum=info[0].weight;            for(i=1;i<n-1;i++)            {                sum+=info[i].weight;                temp=sum-info[i+1].strenth;                if(ans<temp)  ans=temp;            }            if(ans<=0) ans=0;            if(n==1) printf("0\n");            else  printf("%I64d\n",ans);        }        return 0;    }