P2343 宝石管理系统

R70520329

Luogu/P2343/P2343.cpp

@@ -0,0 +1,107 @@
+#include <cstdlib>
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1.1e5 + 5;
+
+int m, q, op, x;
+
+// Treap
+int root, cnt;
+void insert(int);
+int getKth(int);
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin >> m >> q;
+    for (int i = 1; i <= m; i++) {
+        cin >> x;
+        insert(x);
+    }
+    while (q--) {
+        cin >> op >> x;
+        if (op == 1) {
+            cout << getKth(cnt - x + 1) << endl;
+        } else {
+            insert(x);
+        }
+    }
+    return 0;
+}
+
+// === Treap ===
+
+struct node {
+    int l, r, s, v, k;
+
+    node()
+        : l(0), r(0), s(0), v(0), k(rand()) {}
+    node(int _v)
+        : l(0), r(0), s(1), v(_v), k(rand()) {}
+} tr[N];
+
+inline void pushup(int u) {
+    tr[u].s = tr[tr[u].l].s + tr[tr[u].r].s + 1;
+}
+
+std::pair<int, int> split(int p, int k) {
+    if (!p) return std::make_pair(0, 0);
+    if (k <= tr[tr[p].l].s) {
+        auto o = split(tr[p].l, k);
+        tr[p].l = o.second;
+        pushup(p);
+        o.second = p;
+        return o;
+    }
+    auto o = split(tr[p].r, k - tr[tr[p].l].s - 1);
+    tr[p].r = o.first;
+    pushup(p);
+    o.first = p;
+    return o;
+}
+
+std::pair<int, int> splitByValue(int p, int v) {
+    if (!p) return std::make_pair(0, 0);
+    if (tr[p].v < v) {
+        auto o = splitByValue(tr[p].r, v);
+        tr[p].r = o.first;
+        pushup(p);
+        o.first = p;
+        return o;
+    }
+    auto o = splitByValue(tr[p].l, v);
+    tr[p].l = o.second;
+    pushup(p);
+    o.second = p;
+    return o;
+}
+
+int merge(int x, int y) {
+    if (!x || !y) return x | y;
+    if (tr[x].k > tr[y].k) {
+        tr[x].r = merge(tr[x].r, y);
+        pushup(x);
+        return x;
+    }
+    tr[y].l = merge(x, tr[y].l);
+    pushup(y);
+    return y;
+}
+
+void insert(int v) {
+    auto o = splitByValue(root, v);
+    int p = ++cnt;
+    tr[p] = node(v);
+    root = merge(merge(o.first, p), o.second);
+}
+
+int getKth(int k) {
+    auto x = split(root, k - 1);
+    auto y = split(x.second, 1);
+    int r = y.first;
+    root = merge(x.first, merge(y.first, y.second));
+    return tr[r].v;
+}