直接输出1 2 3 4 5

我：。。。。。。

求助QwQ

Code：

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<ctime>
const int M=1e5+5;
class Treap
{
private:
	int s[M],val[M],rnd[M],lazy[M],chi[M][2];
	int cnt,root;
	int undate(int);
	void pushdown(int);
	int merge(int,int);
	void split(int,int,int&,int&);
public:
	int father();
	void push(int);
	void print(int);
	void swap(int,int);
}BST;
int Treap::undate(int now)
{
	s[now]=s[chi[now][0]]+s[chi[now][1]]+1;
}
void Treap::pushdown(int now)
{
	std::swap(chi[now][1],chi[now][0]);
	if(chi[now][0])lazy[chi[now][0]]^=1;
	if(chi[now][1])lazy[chi[now][1]]^=1;
	lazy[now]=0;
}
int Treap::merge(int x,int y)
{
	if(!x||!y)return x+y;
	if(rnd[x]<rnd[y])
	{
		if(lazy[x])pushdown(x);
		return chi[x][1]=merge(chi[x][1],y),undate(x),x;
	}
	else
	{
		if(lazy[y])pushdown(y);
		return chi[y][0]=merge(x,chi[y][0]),undate(y),y;
	}
}
void Treap::split(int now,int k,int&x,int&y)
{
	if(!now)return(void)(x=y=0);
	if(lazy[now])pushdown(now);
	if(k<=s[chi[now][0]])split(chi[y=now][0],k,x,chi[now][0]);
	else split(chi[x=now][1],k-s[chi[now][0]]-1,chi[now][1],y);
	undate(now);
}
int Treap::father()
{
	return root;
}
void Treap::push(int value)
{
	int x,y;
	split(root,value,x,y);++cnt;
	s[cnt]=1;val[cnt]=value;rnd[cnt]=rand();
	root=merge(merge(x,cnt),y);
}
void Treap::print(int now)
{
	if(lazy[now])pushdown(now);
	if(chi[now][0])print(chi[now][0]);
	printf("%d ",val[now]);
	if(chi[now][1])print(chi[now][1]);
}
void Treap::swap(int L,int R)
{
	int x,y,z;
	split(root,R,x,z);split(x,L-1,x,y);
	lazy[x]^=1;root=merge(merge(x,y),z);
}
signed main(void)
{
	srand((unsigned)time(NULL));
	int n,m,L,R;scanf("%d%d",&n,&m);
	for(register int i=1;i<=n;++i)BST.push(i);
	while(m--)scanf("%d%d",&L,&R),BST.swap(L,R);BST.print(BST.father());
}