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2488. 树套树-简单版
https://www.acwing.com/problem/content/submission/code_detail/15807446/
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101
AcWing/2488/2488.cpp
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101
AcWing/2488/2488.cpp
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#include <iostream>
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#include <limits>
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#include <set>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 5e4 + 5;
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int n, m, a[N];
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struct node : public std::multiset<int> {
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int l, r;
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node()
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: l(0), r(0) {}
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node(int _l, int _r)
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: l(_l), r(_r) {
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insert(std::numeric_limits<int>::min());
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insert(std::numeric_limits<int>::max());
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}
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} tr[N << 2];
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void build(int u, int l, int r) {
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tr[u] = node(l, r);
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for (int i = l; i <= r; i++) {
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tr[u].insert(a[i]);
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}
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if (l == r) return;
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int mid = l + r >> 1;
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build(u << 1, l, mid);
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build(u << 1 | 1, mid + 1, r);
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}
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void modify(int u, int p, int x) {
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tr[u].erase(tr[u].find(a[p]));
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tr[u].insert(x);
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if (tr[u].l == tr[u].r) return;
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int mid = tr[u].l + tr[u].r >> 1;
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if (p <= mid) modify(u << 1, p, x);
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else modify(u << 1 | 1, p, x);
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}
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int query(int u, int l, int r, int x) {
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if (l <= tr[u].l && tr[u].r <= r) {
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return *--tr[u].lower_bound(x);
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}
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int mid = tr[u].l + tr[u].r >> 1;
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int res = std::numeric_limits<int>::min();
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if (l <= mid) res = std::max(res, query(u << 1, l, r, x));
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if (r > mid) res = std::max(res, query(u << 1 | 1, l, r, x));
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return res;
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}
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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cin >> n >> m;
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for (int i = 1; i <= n; i++) {
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cin >> a[i];
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}
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build(1, 1, n);
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while (m--) {
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int op;
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cin >> op;
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if (op == 1) {
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int p, x;
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cin >> p >> x;
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modify(1, p, x);
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a[p] = x;
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} else { // op == 2
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int l, r, x;
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cin >> l >> r >> x;
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cout << query(1, l, r, x) << endl;
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}
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}
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return 0;
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}
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