划分树

#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <string.h>
using namespace std;
const int MAXN = 1010;
int tree[20][MAXN];
int sorted[MAXN];
int toleft[20][MAXN];
long long sum[20][MAXN];

void build(int l,int r,int dep)
{
    if(l == r)
    {
        sum[dep][l] = sum[dep][l-1]+tree[dep][l];
        return;
    }
    int mid = (l+r)>>1;
    int same = mid - l + 1;
    for(int i = l; i <= r; i++)
    {
        if(tree[dep][i] < sorted[mid])
            same--;
        sum[dep][i] += sum[dep][i-1]+tree[dep][i];
    }
    int lpos = l;
    int rpos = mid+1;
    for(int i = l; i <= r; i++)
    {
        if(tree[dep][i] < sorted[mid])
            tree[dep+1][lpos++] = tree[dep][i];
        else if(tree[dep][i] == sorted[mid] && same > 0)
        {
            tree[dep+1][lpos++] = tree[dep][i];
            same--;
        }
        else
            tree[dep+1][rpos++] = tree[dep][i];
        toleft[dep][i] = toleft[dep][l-1] + lpos - l;
    }
    build(l,mid,dep+1);
    build(mid+1,r,dep+1);
}
long long ans;
int query(int L,int R,int l,int r,int dep,int k)
{
    if(l == r)return tree[dep][l];
    int mid = (L+R)>>1;
    int cnt = toleft[dep][r] - toleft[dep][l-1];
    if(cnt >= k)
    {
        int ee = r-L+1-(toleft[dep][r]-toleft[dep][L-1])+mid;
        int ss = l-L-(toleft[dep][l-1]-toleft[dep][L-1])+mid;
        ans += sum[dep+1][ee]-sum[dep+1][ss];
        int newl = L + toleft[dep][l-1]-toleft[dep][L-1];
        int newr = newl + cnt -1;
        return query(L,mid,newl,newr,dep+1,k);
    }
    else
    {
        int s = L + toleft[dep][l-1] - toleft[dep][L-1];
        int e = s + cnt - 1;
        ans -= sum[dep+1][e] - sum[dep+1][s-1];
        int newr = r + toleft[dep][R] - toleft[dep][r];
        int newl = newr - (r-l+1-cnt) + 1;
        return query(mid+1,R,newl,newr,dep+1,k-cnt);
    }
}
int main()
{
    int T;
    int n;
    scanf("%d",&T);
    int iCase = 0;
    while(T--)
    {
        iCase++;
        scanf("%d",&n);
        memset(tree,0,sizeof(tree));
        memset(sum,0,sizeof(sum));
        for(int i = 1; i <= n; i++)
        {
            scanf("%d",&tree[0][i]);
            sorted[i] = tree[0][i];
        }
        sort(sorted+1,sorted+n+1);
        build(1,n,0);
        printf("Case #%d:
",iCase);
        int m,l,r;
        scanf("%d",&m);
        while(m--)
        {
            scanf("%d%d",&l,&r);
            l++;
            r++;
            ans = 0;
            int tmp = query(1,n,l,r,0,(l+r)/2-l+1);
            if((l+r)%2)ans-=tmp;
            printf("%lld
",ans);
        }
        printf("
");
    }
    return 0;
}