P2839 [国家集训队]middle

https://www.luogu.com.cn/record/97189566

Luogu/P2839/P2839.cpp

@@ -0,0 +1,159 @@
+#include <iostream>
+#include <algorithm>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e4 + 5;
+
+int n, q, lst;
+int cnt, root[N];
+std::pair<int, int> a[N];
+
+struct node {
+    int l, r, l_max, r_max, sum;
+} tr[N << 5];
+
+void pushup(int u) {
+    tr[u].sum = tr[tr[u].l].sum + tr[tr[u].r].sum;
+    tr[u].l_max = std::max(tr[tr[u].l].l_max, tr[tr[u].l].sum + tr[tr[u].r].l_max);
+    tr[u].r_max = std::max(tr[tr[u].r].r_max, tr[tr[u].r].sum + tr[tr[u].l].r_max);
+}
+
+int build(int l, int r) {
+    int p = ++cnt;
+
+    if (l == r) {
+        tr[p].l_max = tr[p].r_max = tr[p].sum = 1;
+
+        return p;
+    }
+
+    int mid = l + r >> 1;
+
+    tr[p].l = build(l, mid);
+    tr[p].r = build(mid + 1, r);
+
+    pushup(p);
+
+    return p;
+}
+
+int insert(int p, int l, int r, int x, int y) {
+    int q = ++cnt;
+    tr[q] = tr[p];
+
+    if (l == r) {
+        tr[q].l_max = tr[q].r_max = tr[q].sum = y;
+
+        return q;
+    }
+
+    int mid = l + r >> 1;
+
+    if (x <= mid) tr[q].l = insert(tr[q].l, l, mid, x, y);
+    else tr[q].r = insert(tr[q].r, mid + 1, r, x, y);
+
+    pushup(q);
+
+    return q;
+}
+
+int query_sum(int p, int l, int r, int ql, int qr) {
+    if (ql <= l && r <= qr) return tr[p].sum;
+
+    int mid = (l + r) >> 1;
+    int res = 0;
+
+    if (ql <= mid) res += query_sum(tr[p].l, l, mid, ql, qr);
+    if (qr > mid) res += query_sum(tr[p].r, mid + 1, r, ql, qr);
+
+    return res;
+}
+
+int query_l_max(int p, int l, int r, int ql, int qr) {
+    if (ql <= l && r <= qr) return tr[p].l_max;
+
+    int mid = (l + r) >> 1;
+
+    if (qr <= mid) return query_l_max(tr[p].l, l, mid, ql, qr);
+    if (ql > mid) return query_l_max(tr[p].r, mid + 1, r, ql, qr);
+
+    return std::max(query_l_max(tr[p].l, l, mid, ql, qr), query_sum(tr[p].l, l, mid, ql, qr) + query_l_max(tr[p].r, mid + 1, r, ql, qr));
+}
+
+int query_r_max(int p, int l, int r, int ql, int qr) {
+    if (ql <= l && r <= qr) return tr[p].r_max;
+
+    int mid = (l + r) >> 1;
+
+    if (qr <= mid) return query_r_max(tr[p].l, l, mid, ql, qr);
+    if (ql > mid) return query_r_max(tr[p].r, mid + 1, r, ql, qr);
+
+    return std::max(query_r_max(tr[p].r, mid + 1, r, ql, qr), query_sum(tr[p].r, mid + 1, r, ql, qr) + query_r_max(tr[p].l, l, mid, ql, qr));
+}
+
+bool check(int k, int a, int b, int c, int d) {
+    int sum = 0;
+
+    if (b + 1 <= c - 1) sum += query_sum(root[k], 1, n, b + 1, c - 1);
+
+    sum += query_r_max(root[k], 1, n, a, b);
+    sum += query_l_max(root[k], 1, n, c, d);
+
+    return sum >= 0;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i].first;
+
+        a[i].second = i;
+    }
+
+    std::sort(a + 1, a + 1 + n);
+
+    root[0] = build(1, n);
+
+    for (int i = 1; i <= n; i++) {
+        root[i] = insert(root[i - 1], 1, n, a[i].second, -1);
+    }
+
+    cin >> q;
+
+    while (q--) {
+        std::vector<int> q(4);
+
+        for (int& x : q) cin >> x;
+
+        std::transform(q.begin(), q.end(), q.begin(), [&](int x) -> int {
+            return (x + lst) % n + 1;
+        });
+        std::sort(q.begin(), q.end());
+
+        int l = 0, r = n - 1, res = 0;
+
+        while (l <= r) {
+            int mid = (l + r) >> 1;
+
+            if (check(mid, q[0], q[1], q[2], q[3])) {
+                l = mid + 1;
+                res = mid;
+            } else {
+                r = mid - 1;
+            }
+        }
+
+        cout << (lst = a[res + 1].first) << endl;
+    }
+
+    return 0;
+}