[hihoCoder1329] 带Split和Merge的Treap

题目链接：http://hihocoder.com/problemset/problem/1329

这题本来是学Splay的题，但是我为了练习Treap的Split和Merge操作，就借来用一用。

就是砍树然后再合并。

存个代码：

 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 #include <vector>
 #include <map>
 #include <set>
 #include <string>
 #include <bitset>
 #include <cmath>
 #include <numeric>
 #include <iterator>
 #include <iostream>
 #include <cstdlib>
 #include <functional>
 #include <queue>
 #include <stack>
 #include <list>
 #include <ctime>
 using namespace std;

 const int inf = ~0U >> ;

 typedef long long LL;

 struct TreapNode {
     int key, val, siz;
     TreapNode* ch[];
     TreapNode() :val(), siz(){ key = rand(); ch[] = ch[] = NULL; }
     void rz(){
         siz = ;
         if (ch[]) siz += ch[]->siz;
         if (ch[]) siz += ch[]->siz;
     }
     ~TreapNode(){
         if (ch[]) delete ch[];
         if (ch[]) delete ch[];
     }
 };

 typedef pair<TreapNode*, TreapNode*> DTreap;

 void rot(TreapNode*& rt, bool d){
     TreapNode* c = rt->ch[d];
     rt->ch[d] = c->ch[!d];
     c->ch[!d] = rt;
     rt->rz(); c->rz();
     rt = c;
 }

 void Insert(TreapNode*& rt, int val, int key = ) {
     if (!rt){
         rt = new TreapNode();
         rt->val = val;
         if (key) rt->key = key;
         return;
     }
     //if (val == rt->val) return;
     bool d = val > rt->val;
     Insert(rt->ch[d], val, key);
     if (rt->ch[d]->key < rt->key) rot(rt, d);
     else rt->rz();
 }

 void Delete(TreapNode*& rt, int val) {
     if (rt == NULL) return;
     if (rt->val == val) {
         if (rt->ch[] == NULL && rt->ch[] == NULL) {
             delete rt;
             rt = NULL;
             return;
         }
         else if (rt->ch[] == NULL) {
             rot(rt, );
             Delete(rt->ch[], val);
         }
         else if (rt->ch[] == NULL) {
             rot(rt, );
             Delete(rt->ch[], val);
         }
         else {
             bool d = rt->ch[]->key > rt->ch[]->key;
             rot(rt, d);
             Delete(rt->ch[!d], val);
         }
     }
     else {
         bool d = val > rt->val;
         Delete(rt->ch[d], val);
     }
     rt->rz();
 }

 int Kth(TreapNode* rt, int k) {
     if (!rt) return -inf;
     if (rt->siz < k) return -inf;
     int r = ;
     if (!rt->ch[]) r = ;
     else r = rt->ch[]->siz;
     if (r == k - ) return rt->val;
     if (k -  < r) return Kth(rt->ch[], k);
     return Kth(rt->ch[], k - r - );
 }

 DTreap Split(TreapNode* rt, int val) {
     DTreap ret;
     Insert(rt, val, -inf);
     ret.first = rt->ch[];
     ret.second = rt->ch[];
     rt->ch[] = rt->ch[] = NULL;
     delete rt;
     return ret;
 }

 void Merge(DTreap dt, TreapNode*& rt) {
     rt = NULL;
     TreapNode* tch = dt.first?dt.first:dt.second;
     if(tch) {
         TreapNode* nd = new TreapNode();
         nd->key = -inf;
         nd->val = tch->val;
         nd->ch[] = dt.first;
         nd->ch[] = dt.second;
         rt = nd;
         Delete(rt, nd->val);
     }
 }

 int ans;

 void Query(TreapNode* rt, int x) {
     if (rt == NULL) return;
     if (rt->val == x) {
         ans = x;
         return;
     }
     if (rt->val > x) {
         Query(rt->ch[], x);
     }
     else {
         ans = max(ans, rt->val);
         Query(rt->ch[], x);
     }
 }

 char cmd[];
 int a, b, n;

 int main() {
     srand(time(NULL));
     scanf("%d", &n);
     TreapNode* root = NULL;
     for (int i = ; i < n; i++) {
         scanf("%s", cmd);
         if (cmd[] == 'I') {
             scanf("%d", &a);
             Insert(root, a);
         }
         else if (cmd[] == 'Q') {
             ans = -inf;
             scanf("%d", &a);
             Query(root, a);
             printf("%d\n", ans);
         }
         else {
             scanf("%d%d", &a, &b);
             DTreap dt = Split(root, a);
             TreapNode* lch = dt.first;
             TreapNode* rch = dt.second;
             dt = Split(rch, b + );
             if (dt.first) delete dt.first;
             dt.first = lch;
             Merge(dt, root);
         }
     }
     if (root) delete root;
     return ;
 }