Ultraviolet A 11922-permutation Transformer (stretch tree)

Link: Ultraviolet A 11922-permutation Transformer

Given a sequence, each operation extracts the range ~ B. Flip and put it at the end, and then output the sequence.

Solution: stretch the tree. Set a flip for each node to indicate whether it is flipped or not. Each time a is rotated to the root, split, then flip B to the root, split, and put the mid to the end.

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;struct Node {    int val, sum, flip;    Node* cid[2];    Node(int val = 0);    int cmp (int v);    void maintain();    void pushdown();};void rotate (Node* &o, int d);void build(Node* &o, int l, int r);void put(Node* &o);void split (Node* o, int k, Node* &l, Node* & r);Node* merge (Node* l, Node* r);void splay(Node* &o, int k);int main () {    int n, m, x, y;    while (scanf("%d%d", &n, &m) == 2) {        Node* root = NULL;        Node *l, *mid, *r, *o;        build(root, 0, n);        for (int i = 0; i < m; i++) {            scanf("%d%d", &x, &y);            split(root, x, l, o);            split(o, y - x + 1, mid, r);            mid->flip ^= 1;            root = merge(merge(l, r), mid);        }        put(root);    }    return 0;}void splay(Node* &o, int k) {    o->pushdown();    int d = o->cmp(k);    if (d == 1) k -= (o->cid[0] == NULL ? 0 : o->cid[0]->sum) + 1;    if (d != -1) {        Node* p = o->cid[d];        p->pushdown();        int d2 = p->cmp(k);        int k2 = (d2 == 0 ? k : k - (p->cid[0] == NULL ? 0 : p->cid[0]->sum) - 1);        if (d2 != -1) {            splay(p->cid[d2], k2);            if (d == d2)                rotate(o, d^1);            else                rotate(o->cid[d], d);        }        rotate(o, d^1);    }}Node* merge (Node* l, Node* r) {    splay(l, l->sum);    l->cid[1] = r;    l->maintain();    return l;}void split (Node* o, int k, Node* &l, Node* & r) {    splay(o, k);    l = o;    r = o->cid[1];    o->cid[1] = NULL;    l->maintain();}void build(Node* &o, int l, int r) {    if (l > r)        return;    int mid = (l + r) / 2;    o = new Node(mid);    build(o->cid[0], l, mid - 1);    build(o->cid[1], mid + 1, r);    o->maintain();}void rotate (Node* &o, int d) {    Node* k = o->cid[d^1];    o->cid[d^1] = k->cid[d];    k->cid[d] = o;    o->maintain();    k->maintain();    o = k;}void put(Node* &o) {    o->pushdown();    if (o->cid[0] != NULL) put(o->cid[0]);    if (o->val)        printf("%d\n", o->val);    if (o->cid[1] != NULL) put(o->cid[1]);    delete o;    o = NULL;}Node::Node (int val) {    sum = 1;    flip = 0;    this->val = val;    cid[0] = cid[1] = NULL;}int Node::cmp (int v) {    int d = v - (cid[0] == NULL ? 0 : cid[0]->sum);    if (d == 1) return -1;    return d <= 0 ? 0 : 1;}void Node::pushdown() {    if (flip) {        flip = 0;        swap(cid[0], cid[1]);        if (cid[0] != NULL)            cid[0]->flip = !cid[0]->flip;        if (cid[1] != NULL)            cid[1]->flip = !cid[1]->flip;    }}void Node::maintain () {    sum = 1;    if (cid[0] != NULL) sum += cid[0]->sum;    if (cid[1] != NULL) sum += cid[1]->sum;}void remove (Node* &o) {    if (o->cid[0] != NULL) remove(o->cid[0]);    if (o->cid[1] != NULL) remove(o->cid[1]);    delete o;    o = NULL;}

Ultraviolet A 11922-permutation Transformer (stretch tree)