bzoj3224: Tyvj 1728 普通平衡树

链接：http://www.lydsy.com/JudgeOnline/problem.php?id=3224

题意：中文题。

分析：treap模板练习。其实知道了怎么旋转就知道了整个treap啦，实现的时候注意细节即可。

代码：

#include<map>
#include<set>
#include<cmath>
#include<queue>
#include<bitset>
#include<math.h>
#include<vector>
#include<string>
#include<stdio.h>
#include<cstring>
#include<iostream>
#include<algorithm>
#pragma comment(linker, "/STACK:102400000,102400000")
using namespace std;
const int N=15;
const int M=1e5+7;
const int HASHSIZE=3e5+9;
const int mod=100000000;
const int MOD1=1000000007;
const int MOD2=1000000009;
const double EPS=0.00000001;
typedef long long ll;
const ll MOD=1000000007;
const int INF=~0u>>1;
const ll MAX=1ll<<55;
const double pi=acos(-1.0);
typedef double db;
typedef unsigned long long ull;
struct Treap {
struct node {
node *son[2];
int key,siz,wei,cnt;
node(int _key,node *f) {
son[0]=son[1]=f;
key=_key;siz=cnt=1;wei=rand();
}
void pushup() {
siz=son[0]->siz+son[1]->siz+cnt;
}
}*null,*root;
Treap() {
null=new node(0,0);
null->siz=null->siz=0;
null->wei=INF;root=null;
}
void rot(node* &rt,bool d) {
node* c=rt->son[!d];rt->son[!d]=c->son[d];
c->son[d]=rt;rt->pushup();c->pushup();rt=c;
}
void insert(const int &key,node* &rt) {
if (rt==null) {
rt=new node(key,null);return ;
}
if (key==rt->key) {
rt->cnt++;rt->siz++;return ;
}
bool d=key>rt->key;
insert(key,rt->son[d]);
if (rt->wei>rt->son[d]->wei) rot(rt,!d);
rt->pushup();
}
void remove(const int &key,node* &rt) {
if (rt==null) return ;
bool d=key>rt->key;
if (key==rt->key) {
if (rt->cnt>1) {
rt->cnt--;rt->siz--;return ;
}
d=rt->son[0]->wei>rt->son[1]->wei;
if (rt->son[d]==null) {
delete rt;rt=null;return ;
}
rot(rt,!d);remove(key,rt->son[!d]);
} else remove(key,rt->son[d]);
rt->pushup();
}
node* select(int k,node* rt) {
int s=rt->son[0]->siz+rt->cnt;
if (k>=rt->son[0]->siz+1&&k<=s) return rt;
if (s>k) return select(k,rt->son[0]);
else return select(k-s,rt->son[1]);
}
int rank(const int &key,node* rt) {
if (rt==null) return 0;
int s=rt->son[0]->siz+rt->cnt;
if (key==rt->key) return rt->son[0]->siz+1;
if (key<rt->key) return rank(key,rt->son[0]);
else return s+rank(key,rt->son[1]);
}
int pre(const int &k) {
node* t=root;int ret=0;
while (t!=null)
if (t->key<k) ret=t->key,t=t->son[1];
else t=t->son[0];
return ret;
}
int sub(const int &k) {
node* t=root;int ret=0;
while (t!=null)
if (t->key>k) ret=t->key,t=t->son[0];
else t=t->son[1];
return ret;
}
};
int main()
{
int i,a,b,n;
Treap tree;
scanf("%d", &n);
while (n--) {
scanf("%d%d", &a, &b);
if (a==1) tree.insert(b,tree.root);
if (a==2) tree.remove(b,tree.root);
if (a==3) printf("%d\n", tree.rank(b,tree.root));
if (a==4) printf("%d\n", tree.select(b,tree.root)->key);
if (a==5) printf("%d\n", tree.pre(b));
if (a==6) printf("%d\n", tree.sub(b));
}
return 0;
}