正题

题目链接:https://www.luogu.com.cn/problem/U136336?contestId=36038

题目大意

第$i$次找到第$i$大的数字位置$x_i$并且翻转$[i,x_i]$，求输出序列$x$

解题思路

记录一下每个排名在$Splay$中的位置，然后暴力翻转即可。

$code$

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N=1e5+10;
int n,root,t[N][2],val[N],p[N],siz[N],fa[N],r[N];
bool Direct(int x)
{return t[fa[x]][1]==x;}
void Connect(int x,int y,int dir)
{t[x][dir]=y;fa[y]=x;return;}
void PushUp(int x)
{siz[x]=siz[t[x][0]]+siz[t[x][1]]+1;return;}
void rev(int x){
	swap(t[x][0],t[x][1]);
	r[x]^=1;return;
}
void PushDown(int x){
	if(!r[x])return;
	rev(t[x][0]);rev(t[x][1]);
	r[x]=0;return;
}
void Rotate(int x){
	PushDown(fa[x]);PushDown(x);
	int y=fa[x],z=fa[y];
	int xs=Direct(x),ys=Direct(y);
	Connect(y,t[x][xs^1],xs); 
	Connect(x,y,xs^1);
	Connect(z,x,ys);
	PushUp(y);PushUp(x);
	return;
}
void Downdata(int x){
	if(!x)return;
	Downdata(fa[x]);
	PushDown(x);
	return;
}
void Splay(int x,int z){
	Downdata(x);
	while(fa[x]!=z){
		int y=fa[x];
		if(fa[y]==z)Rotate(x);
		else if(Direct(x)==Direct(y))
			Rotate(y),Rotate(x);
		else Rotate(x),Rotate(x);
	}
	if(!z)root=x;
	return;
} 
int rk(int x){
	Splay(x,0);
	return siz[t[x][0]];
}
int find(int x,int k){
	PushDown(x);
	if(k<=siz[t[x][0]])return find(t[x][0],k);
	if(siz[t[x][0]]+1==k)return x;
	return find(t[x][1],k-siz[t[x][0]]-1);
}
bool cmp(int x,int y){
	if(val[x+1]==val[y+1])return x<y;
	return val[x+1]<val[y+1];
}
void print(int x){
	if(!x)return;
	print(t[x][0]);
	printf("%d ",val[x]);
	print(t[x][1]);
}
int main()
{
	freopen("31.in","r",stdin);
	freopen("data.out","w",stdout);
	scanf("%d",&n);siz[1]=1;
	for(int i=2;i<=n+1;i++){
		scanf("%d",&val[i]);
		t[i][0]=i-1;fa[i-1]=i;
		p[i-1]=i-1;PushUp(i);
	}
	sort(p+1,p+1+n,cmp);
	t[n+2][0]=n+1;fa[n+1]=n+2;
	PushUp(n+2);root=n+2;
	for(int i=1;i<=n;i++){
		int w=rk(p[i]+1);
 		printf("%d ",w);
//		print(root);putchar('\n');
		int x=find(root,i),y=find(root,w+2);
		Splay(x,0);
		Splay(y,x); 
		rev(t[y][0]);
//		print(root);putchar('\n');
	}
	return 0;
}

本文地址：https://blog.csdn.net/Mr_wuyongcong/article/details/109276339