Treap求调
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Treap求调
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Calvin_Wang楼主2024/1/15 22:21

RT

#include<bits/stdc++.h>
#define int long long
#define endl '\n'
using namespace std;

const int N=100010,INF=INT_MAX;
struct treap{
	int l,r,key,val,cnt,size;
}tr[N]; 
int n,root,idx;

void push_up(int p){
	tr[p].size=tr[tr[p].l].size+tr[tr[p].r].size+tr[p].cnt;
}

int get_node(int key){
	tr[++idx].key=key;
	tr[idx].val=rand();
	tr[idx].cnt=tr[idx].size=1;
	return idx;
}

void build(){
	get_node(-INF);
	get_node(INF);
	root=1;
	tr[1].r=2;
	push_up(root);
}

void rotate_right(int &p){
	int q=tr[p].l;
	tr[p].l=tr[q].r;
	tr[q].r=p;
	p=q;
	push_up(tr[p].r);
	push_up(p);
}

void rotate_left(int &p){
	int q=tr[p].r;
	tr[p].r=tr[q].l;
	tr[q].l=p;
	p=q;
	push_up(tr[p].l);
	push_up(p);
}

void insert(int &p,int key){
	if(!p){
		p=get_node(key);
	}else if(tr[p].key==key){
		tr[p].cnt++;
	}else if(tr[p].key>key){
		insert(tr[p].l,key);
		if(tr[tr[p].l].val>tr[p].val){
			rotate_right(p);
		}
	}else{
		insert(tr[p].r,key);
		if(tr[tr[p].r].val>tr[p].val){
			rotate_left(p);
		}
	}
	push_up(p);
}

void remove(int &p,int key){
	if(!p){
		return;
	}
	if(tr[p].key==key){
		if(tr[p].cnt>1){
			tr[p].cnt--;
		}else if(tr[p].l||tr[p].r){
			if(!tr[p].r||tr[tr[p].l].val>tr[tr[p].r].val){
				rotate_right(p);
				remove(tr[p].r,key);
			}else{
				rotate_left(p);
				remove(tr[p].l,key);
			}
		}else{
			p=0;
		}
	}else if(tr[p].key>key){
		remove(tr[p].l,key);
	}else{
		remove(tr[p].r,key);
	}
	push_up(p);
}

int get_rank_by_key(int &p,int key){
	if(!p){
		return 0;
	}
	if(tr[p].key==key){
		return tr[tr[p].l].size+1;
	}else if(tr[p].key>key){
		return get_rank_by_key(tr[p].l,key);
	}else{
		return tr[tr[p].l].size+tr[p].cnt+get_rank_by_key(tr[p].r,key);
	}
}

int get_key_by_rank(int &p,int rank){
	if(!p){
		return INF;
	}
	if(tr[tr[p].l].size>=rank){
		return get_key_by_rank(tr[p].l,rank);
	}else if(tr[tr[p].l].size+tr[p].cnt>=rank){
		return tr[p].key;
	}else{
		return get_key_by_rank(tr[p].r,rank-tr[tr[p].l].size-tr[p].cnt);
	}
}

int get_prev(int &p,int key){
	if(!p){
		return -INF;
	}
	if(tr[p].key>=key){
		return get_prev(tr[p].l,key);
	}
	return max(tr[p].key,get_prev(tr[p].r,key));
}

int get_next(int &p,int key){
	if(!p){
		return INF;
	}
	if(tr[p].key<=key){
		return get_prev(tr[p].r,key);
	}
	return min(tr[p].key,get_next(tr[p].l,key));
}

signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	build();
	cin>>n;
	while(n--){
		int opt,x;
		cin>>opt>>x;
		if(opt==1){
			insert(root,x);
		}else if(opt==2){
			remove(root,x);
		}else if(opt==3){
			cout<<get_rank_by_key(root,x)-1<<endl;
		}else if(opt==4){
			cout<<get_key_by_rank(root,x)+1<<endl;
		}else if(opt==5){
			cout<<get_prev(root,x)<<endl;
		}else{
			cout<<get_next(root,x)<<endl;
		}
	}
	return 0;
}
2024/1/15 22:21
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