伸展树模板

---

#include <iostream>
#include <cstdio>#define pr(x) std::cout << #x << " : " << x << std::endlclass SplayTree{
public:struct Node{int val;int size;int tag;Node *father;Node *son[2];Node(int val,Node *father) {this -> son[0] = this -> son[1] = NULL;this -> tag = 0;this -> val = val;this -> father = father;}}*root;SplayTree(){root = NULL;}inline bool son(Node *f,Node *s) {return f && f -> son[1] == s;}inline void connect(Node *f,Node *s,bool k) {if(f == NULL)root = s;elsef -> son[k] = s;if(s != NULL)s -> father = f;}inline void maintain(Node *t) {t -> size = 1;if(t -> son[0]) t -> size += t -> son[0] -> size;if(t -> son[1]) t -> size += t -> son[1] -> size;}inline void rotate(Node *t) {Node *f = t -> father;Node *g = f -> father;pushdown(f);pushdown(t);bool a = son(f,t);connect(f,t->son[!a],a);connect(g,t,son(g,f));connect(t,f,!a);maintain(f);maintain(t);}inline void splay(Node *t,Node *p) {while(p != t -> father) {Node *f = t -> father;Node *g = f -> father;if(g == p) {rotate(t);}else {if(son(g,f) ^ son(f,t))rotate(t),rotate(t);elserotate(f),rotate(t);}}}inline void insert(int val) {if(root == NULL) {root = new Node(val,NULL);return ;}for(Node* t = root;t;t = t -> son[val > t -> val]) {pushdown(t);bool a = val > t -> val;if(t -> son[a] == NULL) {t -> son[a] = new Node(val,t);//maintain(t);splay(t -> son[a],NULL);break;}}}inline void erase(int k) {if(!root || root -> size <= 1) {root = NULL;return ;}if(k == 1) {splay(select(root, k),NULL);pushdown(root);root = root -> son[1];root -> father = NULL;}else if(k == root -> size) {splay(select(root, k),NULL);pushdown(root);root = root -> son[0];root -> father = NULL;}else {splay(select(root, k-1),NULL);splay(select(root, k+1),root);pushdown(root);pushdown(root -> son[1]);root -> son[1] -> son[0] = NULL;maintain(root -> son[1]);maintain(root);}}inline Node* select(Node *t,int k) {pushdown(t);int left = 0;if(t -> son[0]) left += t -> son[0] -> size;if(k == left + 1)return t;if(k <= left)return select(t -> son[0],k);elsereturn select(t -> son[1],k - left - 1);}inline Node* lower_bound(int val) {//不适用于翻转操作,因此不需pushdownif(!root)return NULL;Node* ans = NULL;for(Node *t = root;t;t = t -> son[val > t -> val]) {if(t -> val >= val) ans = t;}return ans;}inline void reverse(Node *t) {if(t)t -> tag ^= 1;}inline void pushdown(Node *t) {if(t && t -> tag) {std::swap(t -> son[0],t -> son[1]);reverse(t -> son[0]);reverse(t -> son[1]);t -> tag ^= 1;}}
};
int n,m;
int main()
{SplayTree tree;std::ios::sync_with_stdio(false);std::cin >> m;while(m --) {int tp;std::cin >> tp;if(tp == 1) {//插入一个数xint x;std::cin >> x;tree.insert(x);}else if(tp == 2) {//删除数值为x的数int x;std::cin >> x;auto res = tree.lower_bound(x);if(res && res -> val == x) {tree.splay(res,NULL);int k = (tree.root -> son[0] ? tree.root -> son[0] -> size:0) + 1;tree.erase(k);}}else if(tp == 3) {//输出数值为x的数的排名int x;std::cin >> x ;auto res = tree.lower_bound(x);if(res == NULL) {std::cout << res->size + 1 << std::endl;continue;}tree.splay(res,NULL);int k = 1;if(res -> son[0]) k += res -> son[0] -> size;std::cout << k << std::endl;}else if(tp == 4) {//找到第k个数字int k;std::cin >> k;std::cout << tree.select(tree.root,k)->val << std::endl;}else if(tp == 5) {//输出比x小的最大的数int x;std::cin >> x;int ans = -1000000000;for(auto t = tree.root;t;t = t -> son[x > t -> val]) {if(t -> val < x && t -> val > ans) ans = t -> val;}std::cout << ans << std::endl;}else {//输出比x大的最小的数int x;std::cin >> x;int ans = 1000000000;for(auto t = tree.root;t;t = t -> son[x >= t -> val]) {if(t -> val > x && t -> val < ans) ans = t -> val;}std::cout << ans << std::endl;}}return 0;
}