Luogu P2824 [HEOI2016/TJOI2016]排序

题目链接：​​传送门​​

好久之前qbxt上听的
只有一次询问，二分这个数
二分的是大于等于mid的数中有没有符合条件的数
对于每次二分的结果重新建树
大于等于这个数的节点设为1否则为0
这样的话排序就是询问区间1的个数然后01覆盖
最后看那个位置上是不是1就可以了
是1说明这个数大于等于mid

/**
 * @Date:   2019-03-14T14:24:40+08:00
 * @Last modified time: 2019-03-14T14:24:41+08:00
 */
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <complex>
#include <algorithm>
#include <climits>
#include <queue>
#include <map>
#include <set>
#include <vector>
#include <iomanip>
#define
#define

using namespace std;
typedef long long ll;
struct node {
    int l, r, w, f;
}tree[A];
struct N {
    int opt, l, r;
}q[A];
int n, m, ini[A], pre[A], a, b, c, ans, pos;
void build(int k, int l, int r) {
    tree[k].l = l; tree[k].r = r; tree[k].f = -1;
    if (l == r) {
        tree[k].w = pre[l];
        return;
    }
    int m = (l + r) >> 1;
    build(k << 1, l, m);
    build(k << 1 | 1, m + 1, r);
    tree[k].w = tree[k << 1].w + tree[k << 1 | 1].w;
}
void down(int k) {
    tree[k << 1].f = tree[k].f;
    tree[k << 1 | 1].f = tree[k].f;
    tree[k << 1].w = (tree[k << 1].r - tree[k << 1].l + 1) * tree[k].f;
    tree[k << 1 | 1].w = (tree[k << 1 | 1].r - tree[k << 1 | 1].l + 1) * tree[k].f;
    tree[k].f = -1;
}
void ask(int k) {
    if (tree[k].l >= a and tree[k].r <= b) {
        ans += tree[k].w;
        return;
    }
    if (tree[k].f != -1) down(k);
    int m = (tree[k].l + tree[k].r) >> 1;
    if (a <= m) ask(k << 1);
    if (b > m) ask(k << 1 | 1);
}
void change(int k) {
    if (tree[k].l >= a and tree[k].r <= b) {
        tree[k].w = (tree[k].r - tree[k].l + 1) * c;
        tree[k].f = c;
        return;
    }
    if (tree[k].f != -1) down(k);
    int m = (tree[k].l + tree[k].r) >> 1;
    if (a <= m) change(k << 1);
    if (b > m) change(k << 1 | 1);
    tree[k].w = tree[k << 1].w + tree[k << 1 | 1].w;
}
bool work(int mid) {
    for (int i = 1; i <= n; i++) pre[i] = (ini[i] >= mid);
    build(1, 1, n);
    for (int i = 1; i <= m; i++) {
        a = q[i].l, b = q[i].r, ans = 0, ask(1);
        if (q[i].opt) {
            a = q[i].l, b = q[i].l + ans - 1, c = 1, change(1);
            a = q[i].l + ans, b = q[i].r, c = 0, change(1);
        }
        else {
            a = q[i].l, b = q[i].r - ans, c = 0, change(1);
            a = q[i].r - ans + 1, b = q[i].r, c = 1, change(1);
        }
    }
    a = pos, b = pos, ans = 0, ask(1);
    return ans;
}

int main(int argc, char const *argv[]) {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> ini[i];
    for (int i = 1; i <= m; i++) cin >> q[i].opt >> q[i].l >> q[i].r;
    cin >> pos;
    int l = 1, r = n;
    while (l <= r) {
        int m = (l + r) >> 1;
        if (work(m)) l = m + 1;
        else r = m - 1;
    }
    cout << r << endl;
    return 0;
}