hdu3473 划分树

直接套用划分树模板即可。

ACcode:

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long LL;
const int NS=100010;

struct node{
    LL sum[NS];
    int num[NS];
    int val[NS];
}row[18];

int n,m;
int st[NS];
LL sum[NS];
LL tot;

void build(int dep,int L,int R)
{
    if (L==R) return ;
    int mid=(L+R)>>1;
    int same=mid-L+1;
    int idl=L,idr=mid+1;
    for (int i=L;i<=R;i++)
    if (row[dep].val[i]<st[mid]) same--;

    for (int i=L;i<=R;i++)
    {
        if (i==L) {
            row[dep].sum[i]=0;
            row[dep].num[i]=0;
        } else {
            row[dep].sum[i]=row[dep].sum[i-1];
            row[dep].num[i]=row[dep].num[i-1];
        }

        if (row[dep].val[i]<st[mid]) {
            row[dep].num[i]++;
            row[dep].sum[i]+=row[dep].val[i];
            row[dep+1].val[idl++]=row[dep].val[i];
        } else if (row[dep].val[i]>st[mid]) {
            row[dep+1].val[idr++]=row[dep].val[i];
        } else {
            if (same>0){
                same--;
                row[dep].num[i]++;
                row[dep].sum[i]+=row[dep].val[i];
                row[dep+1].val[idl++]=row[dep].val[i];
            } else {
                row[dep+1].val[idr++]=row[dep].val[i];
            }
        }
    }
    build(dep+1,L,mid);
    build(dep+1,mid+1,R);
}

int query(int dep,int k,int x,int y,int L,int R)
{
    if (L==R) return row[dep].val[L];
    LL sxy;
    int a,b,ctl,ctm;
    int mid=(L+R)>>1;

    if (x==L) {
        ctl=0;
        ctm=row[dep].num[y];
        sxy=row[dep].sum[y];
    } else {
        ctl=row[dep].num[x-1];
        ctm=row[dep].num[y]-ctl;
        sxy=row[dep].sum[y]-row[dep].sum[x-1];
    }

    if (ctm>=k) {
        a=L+ctl;
        b=a+ctm-1;
        R=mid;
    } else {
        a=mid+1+(x-L-ctl);
        b=a+(y-x+1-ctm)-1;
        tot+=sxy;
        L=mid+1;
        k-=ctm;
    }
    return query(dep+1,k,a,b,L,R);
}

int main()
{
    int T,cas=1;
    for (scanf("%d",&T);cas<=T;cas++)
    {
        scanf("%d",&n);
        sum[0]=0;
        memset(row,0,sizeof(row));
        for (int i=1;i<=n;i++)
        {
            scanf("%d",&st[i]);
            row[0].val[i]=st[i];
            sum[i]=sum[i-1]+st[i];
        }
        sort(st+1,st+n+1);
        build(0,1,n);

        scanf("%d",&m);
        printf("Case #%d:\n",cas);
        while (m--)
        {
            int x,y,k;
            scanf("%d %d",&x,&y),tot=0;
            x++,y++,k=(y-x+2)>>1;
            int nl=k-1,nr=y-x-k+2;
            LL tmp=query(0,k,x,y,1,n);
            LL suml=tot,sumr=sum[y]-sum[x-1]-tot;
            suml=tmp*nl-suml,sumr=sumr-tmp*nr;
            tmp=suml+sumr;
            printf("%I64d\n",tmp);
        }
        puts("");
    }
    return 0;
}