【UOJ #29】【IOI 2014】holiday

#include<cstdio>
#include<cstring>
#include<algorithm>
#include"holiday.h"
using namespace std;
typedef long long ll;
const int N = 100003;
const int M = 250003;

struct node {
    int l, r, s;
    ll sum;
    node() {l = r = s = sum = 0;}
} T[N * 20];
int a[N], H[N], cnt = 0, root[N], top, st;
ll f[M], g[M], f1[M], g1[M];

void update(int &pos, int l, int r, int key) {
    T[++cnt] = T[pos]; pos = cnt;
    ++T[pos].s; T[pos].sum += H[key];
    if (l == r) return;
    int mid = (l + r) >> 1;
    if (key <= mid) update(T[pos].l, l, mid, key);
    else update(T[pos].r, mid + 1, r, key);
}

ll query(int tl, int tr, int l, int r, int num) {
    if (l == r) {return min(T[tr].sum - T[tl].sum, 1ll * H[l] * num);}
    int mid = (l + r) >> 1, s = T[T[tr].r].s - T[T[tl].r].s;
    if (s >= num)
        return query(T[tl].r, T[tr].r, mid + 1, r, num);
    else
        return T[T[tr].r].sum - T[T[tl].r].sum + query(T[tl].l, T[tr].l, l, mid, num - s);
}

void cdq_f(int l, int r, int tmp_l, int tmp_r) {
    if (l > r) return;
    int mid = (l + r) >> 1, pos = tmp_l;
    ll t;
    for(int i = tmp_l; i - st <= mid && i <= tmp_r; ++i)
        if ((t = query(root[st - 1], root[i], 1, top, mid - i + st)) > f[mid])
            f[mid] = t, pos = i;
    cdq_f(l, mid - 1, tmp_l, pos);
    cdq_f(mid + 1, r, pos, tmp_r);
}

void cdq_f1(int l, int r, int tmp_l, int tmp_r) {
    if (l > r || tmp_l > tmp_r) return;
    int mid = (l + r) >> 1, pos = tmp_l;
    ll t;
    for(int i = tmp_l; ((i - st) << 1) <= mid && i <= tmp_r; ++i)
        if ((t = query(root[st], root[i], 1, top, mid - ((i - st) << 1))) > f1[mid])
            f1[mid] = t, pos = i;
    cdq_f1(l, mid - 1, tmp_l, pos);
    cdq_f1(mid + 1, r, pos, tmp_r);
}

void cdq_g(int l, int r, int tmp_l, int tmp_r) {
    if (l > r) return;
    int mid = (l + r) >> 1, pos = tmp_r;
    ll t;
    for(int i = tmp_r; st - i <= mid && i >= tmp_l; --i) {
        if ((t = query(root[i - 1], root[st], 1, top, mid - st + i)) > g[mid])
            g[mid] = t, pos = i;
    }
    cdq_g(l, mid - 1, pos, tmp_r);
    cdq_g(mid + 1, r, tmp_l, pos);
}

void cdq_g1(int l, int r, int tmp_l, int tmp_r) {
    if (l > r || tmp_l > tmp_r) return;
    int mid = (l + r) >> 1, pos = tmp_r;
    ll t;
    for(int i = tmp_r; ((st - i) << 1) <= mid && i >= tmp_l; --i) {
        if ((t = query(root[i - 1], root[st - 1], 1, top, mid - ((st - i) << 1))) > g1[mid])
            g1[mid] = t, pos = i;
    }
    cdq_g1(l, mid - 1, pos, tmp_r);
    cdq_g1(mid + 1, r, tmp_l, pos);
}

ll findMaxAttraction(int n, int start, int d, int attraction[]) {
    for(int i = 0; i < n; ++i) H[++cnt] = attraction[i];
    sort(H + 1, H + cnt + 1);
    cnt = unique(H + 1, H + cnt + 1) - H;
    for(int i = 1; i <= n; ++i) a[i] = lower_bound(H + 1, H + cnt, attraction[i - 1]) - H;
    top = cnt - 1; cnt = 0;
    
    for(int i = 1; i <= n; ++i) {
        root[i] = root[i - 1];
        update(root[i], 1, top, a[i]);
    }
    
    st = start + 1;
    cdq_f(0, d, st, n);
    cdq_f1(0, d, st + 1, n);
    cdq_g(0, d, 1, st);
    cdq_g1(0, d, 1, st - 1);
    
    ll ans = max(f[d], g[d]);
    for(int i = 1; i <= d; ++i)
        ans = max(ans, max(f[i] + g1[d - i], g[i] + f1[d - i]));
    return ans;
}