P4402 [Cerc2007]robotic sort 机械排序

https://www.luogu.com.cn/record/79454678

Luogu/P4402/P4402.cpp

@@ -0,0 +1,183 @@
+#include <iostream>
+#include <algorithm>
+#include <chrono>
+#include <limits>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+struct node {
+    node *lchild, *rchild;
+    size_t size;
+    unsigned key;
+    int value, min;
+    bool reversed;
+
+    node()
+        : lchild(nullptr),
+          rchild(nullptr),
+          size(0),
+          key(rand()),
+          value(0),
+          min(std::numeric_limits<int>::max()),
+          reversed(false) {}
+
+    node(int _value)
+        : lchild(nullptr),
+          rchild(nullptr),
+          size(1),
+          key(rand()),
+          value(_value),
+          min(_value),
+          reversed(false) {}
+
+    ~node() {
+        if (lchild != nullptr) delete lchild;
+        if (rchild != nullptr) delete rchild;
+    }
+
+    inline size_t lsize() {
+        return lchild == nullptr ? 0 : lchild->size;
+    }
+
+    inline size_t rsize() {
+        return rchild == nullptr ? 0 : rchild->size;
+    }
+
+    inline void pushup() {
+        size = lsize() + 1 + rsize();
+        min = value;
+
+        if (lchild != nullptr) {
+            min = std::min(min, lchild->min);
+        }
+
+        if (rchild != nullptr) {
+            min = std::min(min, rchild->min);
+        }
+    }
+
+    inline void pushdown() {
+        if (reversed) {
+            std::swap(lchild, rchild);
+            if (lchild != nullptr) lchild->reversed = !lchild->reversed;
+            if (rchild != nullptr) rchild->reversed = !rchild->reversed;
+            reversed = false;
+        }
+    }
+};
+
+int n, b[N];
+std::pair<int, int> a[N];
+node *root;
+
+std::pair<node *, node *> split(node *u, int k) {
+    if (u == nullptr) return std::make_pair(nullptr, nullptr);
+
+    u->pushdown();
+
+    if (k <= u->lsize()) {
+        auto o = split(u->lchild, k);
+
+        u->lchild = o.second;
+        u->pushup();
+        o.second = u;
+
+        return o;
+    }
+
+    auto o = split(u->rchild, k - u->lsize() - 1);
+
+    u->rchild = o.first;
+    u->pushup();
+    o.first = u;
+
+    return o;
+}
+
+node *merge(node *x, node *y) {
+    if (x == nullptr) return y;
+    if (y == nullptr) return x;
+
+    if (x->key < y->key) {
+        x->pushdown();
+        x->rchild = merge(x->rchild, y);
+        x->pushup();
+
+        return x;
+    }
+
+    y->pushdown();
+    y->lchild = merge(x, y->lchild);
+    y->pushup();
+
+    return y;
+}
+
+void reverse(int k) {
+    auto x = split(root, k);
+    auto y = split(x.first, k - 1);
+    if (y.first != nullptr) y.first->reversed = !y.first->reversed;
+    delete y.second;
+    root = merge(y.first, x.second);
+}
+
+int find(node *p) {
+    int k = 1;
+
+    while (p != nullptr) {
+        p->pushdown();
+
+        if (p->lchild != nullptr && p->min == p->lchild->min) {
+            p = p->lchild;
+        } else if (p->rchild != nullptr && p->min == p->rchild->min) {
+            k += p->lsize() + 1;
+            p = p->rchild;
+        } else {
+            return k + p->lsize();
+        }
+    }
+
+    return -1;
+}
+
+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);
+
+    for (int i = 1; i <= n; i++) {
+        b[a[i].second] = i;
+    }
+
+    for (int i = 1; i <= n; i++) {
+        root = merge(root, new node(b[i]));
+    }
+
+    for (int i = 1; i <= n; i++) {
+        int k = find(root);
+
+        reverse(k);
+
+        cout << k + i - 1 << ' ';
+    }
+
+    cout << endl;
+
+    // Cleanup
+    delete root;
+
+    return 0;
+}