hdu 3473 Minimum Sum(划分树-sum操作)

标签：划分树

           划分树。只是考虑求当前区间大于第k值的值得和，和小于第k值的和。显然可以在查询的时候直接搞出来。sum[d][i]表示第d层子区间l,r种l-i的和。写错了一个下标，检查了半辈子。。。

#include<algorithm>
#include<iostream>
#include<cstring>
#include<vector>
#include<cstdio>
#include<cmath>
#include<queue>
#include<stack>
#include<map>
#include<set>
#define MP make_pair
#define LL long long
#define CLR(a, b) memset(a, b, sizeof(a))

using namespace std;

#define MID ((l+r)>>1)

const int maxn = 100100;
const int INF = 0x3f3f3f3f;

struct KthNumber
{
    int a[maxn], s[maxn], t[20][maxn], num[20][maxn];
    LL sum[20][maxn];

    void init(int n)
    {
        for(int i = 1; i <= n; i ++)
        {
            scanf("%d", &a[i]);
            s[i] = t[0][i] = a[i];
        }
        sort(s+1, s+n+1);
    }

    void Build(int d, int l, int r)
    {
        int lm = MID-l+1, lp = l, rp = MID+1;
        for(int i = l; i <= MID; i ++)
            lm -= s[i] < s[MID];
        for(int i = l; i <= r; i ++)
        {
            if(i == l) num[d][i] = 0, sum[d][i] = 0;
            else num[d][i] = num[d][i - 1], sum[d][i] = sum[d][i-1];

            if(t[d][i] == s[MID])
            {
                if(lm)
                {
                    lm --; num[d][i] ++;
                    t[d+1][lp++] = t[d][i];
                }
                else t[d+1][rp++] = t[d][i];
            }
            else if(t[d][i] < s[MID])
            {
                num[d][i] ++;
                t[d+1][lp++] = t[d][i];
            }
            else t[d+1][rp++] = t[d][i];
            sum[d][i] += t[d][i];
        }
        if(l<r)
            Build(d+1, l, MID), Build(d+1, MID+1, r);
    }

    int Query(int d, int l, int r, int ql, int qr, int k)
    {
        if(l == r) return t[d][l];
        int s, ss;
        if(l == ql) s = 0, ss = num[d][qr];
        else s = num[d][ql-1], ss = num[d][qr]-num[d][ql-1];
        if(k <= ss) return Query(d+1, l, MID, l+s, l+s+ss-1, k);
        else return Query(d+1, MID+1, r, MID+1+ql-l-s, MID+1+qr-l-s-ss, k-ss);
    }

    int val;

    LL Query2(int d, int l, int r, int ql, int qr, int k)
    {
        if(l == r)
        {
            val = t[d][l];
            return 0;
        }
        int s, ss;LL ret;
        if(l == ql) s = 0, ss = num[d][qr];
        else s = num[d][ql-1], ss = num[d][qr]-num[d][ql-1];
        int l1 = l+s, r1 = l+s+ss-1, l2 = MID+1+ql-l-s, r2 = MID+1+qr-l-s-ss;

        if(k <= ss)
        {
            ret = Query2(d+1, l, MID, l1, r1, k);
            if(l2 <= r2) ret += sum[d+1][r2] - (l2 == MID+1 ? 0 : sum[d+1][l2 - 1]) - (r2-l2+1ll)*val;
        }
        else
        {
            ret = Query2(d+1, MID+1, r, l2, r2, k-ss);
            if(l1 <= r1) ret += (r1-l1+1ll)*val - sum[d+1][r1] + (l1 == l ? 0 : sum[d+1][l1 - 1]);
        }
        return ret;
    }
}sol;

int main()
{
    int n, m, T, cas = 1;
    scanf("%d", &T);
    while(T --)
    {
        scanf("%d", &n);
        sol.init(n);
        sol.Build(0, 1, n);
        scanf("%d", &m);
        printf("Case #%d:\n", cas ++);
        while(m --)
        {
            int l, r, k;
            scanf("%d%d", &l, &r);
            l ++, r ++;k = (r-l+2)/2;
            printf("%I64d\n", sol.Query2(0, 1, n, l, r, k));
        }
        puts("");
    }
}

hdu 3473 Minimum Sum(划分树-sum操作),布布扣,bubuko.com

hdu 3473 Minimum Sum(划分树-sum操作)

标签：划分树

原文地址：http://blog.csdn.net/ok_again/article/details/25790961