真滴难受，调三小时了，样例只输出5

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
int n,m,cnt,l,r,root,a[N];
struct node{
	int ch[2],fa,size,tag,val;
}spl[N];
#define ls(x) spl[x].ch[0]
#define rs(x) spl[x].ch[1]
inline int ident(int x,int f){return rs(x)==x;}
inline void update(int now)
{
	spl[now].size=spl[ls(now)].size+spl[rs(now)].size+1;
	return;
}
inline void pushdown(int now)
{
	if(!spl[now].tag||!now)return;
	spl[ls(now)].tag^=1;
	spl[rs(now)].tag^=1;
	swap(ls(now),rs(now));
	spl[now].tag=0;
	return;
}
inline void connect(int x,int f,int s)
{
	spl[f].ch[s]=x;
	spl[x].fa=f;
	return;
}
inline void newnode(int &now,int fa,int val)
{
	spl[now=++cnt].val=val;
	spl[cnt].fa=fa;
	spl[cnt].size=1;
	return;
}
inline void rotate(int x)
{
	int f=spl[x].fa,ff=spl[f].fa,k=ident(x,f);
	pushdown(f),pushdown(x);
	connect(spl[x].ch[k^1],f,k);
	connect(x,ff,ident(f,ff));
	connect(f,x,k^1);
	update(f),update(x);
	return;
}
inline void splaying(int x,int top)
{
	if(!top)root=x;
	while(spl[x].fa!=top)
	{
		int f=spl[x].fa,ff=spl[f].fa;
		if(ff!=top)ident(f,ff)^ident(x,f)?rotate(x):rotate(f);
		rotate(x);
	}
	return;
}
inline int  build(int l,int r,int fa=0)
{
	if(l>r)return 0;
	int mid=l+r>>1;
	int now=++cnt;
	spl[now]={{0,0},fa,1,0,a[mid]};
	ls(now)=build(l,mid-1,now);
	rs(now)=build(mid+1,r,now);
	update(now);
	return now;
}
inline int getnum(int rank)
{
	int x=root,y=rank;
	while(x)
	{
		pushdown(x);
		if(y<=spl[ls(x)].size)x=ls(x);
		else
		{
			y-=spl[ls(x)].size+1;
			if(!y)return x;
			x=rs(x);
		}
	}
}
inline void reverse(int l,int r)
{
	l=getnum(l-1),r=getnum(r+1);
	splaying(l,0);
	splaying(r,l);
	spl[ls(rs(root))].tag^=1;
	return;
}
inline void ldr(int now)
{
	pushdown(now);
	if(ls(now))ldr(ls(now));
	if(spl[now].val!=-0x3f3f3f3f&&spl[now].val!=0x3f3f3f3f)cout<<spl[now].val<<" ";
	if(rs(now))ldr(rs(now));
	return;
}
int main()
{
	clock_t c1=clock();
#ifdef LOCAL
 	freopen("1.in","r",stdin);
 	freopen("1.out","w",stdout);
#endif
    ios::sync_with_stdio(0);
 	cin.tie(0);cout.tie(0);
	cin>>n>>m;
	a[1]=-0x3f3f3f3f,a[n+2]=0x3f3f3f3f;
	for(int i=1;i<=n;i++)
	{
		a[i+1]=i;
	}
	root=build(1,n+2);
	while(m--)
	{
		cin>>l>>r;
		int tx=getnum(l),ty=getnum(r+2);
		splaying(tx,0);
		splaying(ty,tx);
		spl[ls(rs(root))].tag^=1;
	}
	ldr(root);
#ifdef LOCAL
	cerr<<"Time used:"<<clock()-c1<<"ms";
#endif
 	return 0;
}