@[_O_v_O_](/user/782941)
死因：
自己看吧（）
```cpp
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ls(x) tr[x].lson
#define rs(x) tr[x].rson
const int N=1e5+5;
int n,m,a,last,ans;
struct fhq{
struct node{int lson,rson;int val,pri;int siz,lazy;};
int root;node tr[N];
void pushup(int x){tr[x].siz=tr[ls(x)].siz+tr[rs(x)].siz+1;}
void pushdown(int x){
swap(ls(x),rs(x));
tr[ls(x)].lazy^=1;tr[rs(x)].lazy^=1;
tr[x].lazy=0;
}
void newnode(int x){tr[x]={0,0,x,rand(),1,0};}
void split(int u,int v,int &x,int &y){
if(!u){x=y=0;return;}
if(tr[u].lazy) pushdown(u);
if(tr[ls(u)].siz+1<=v) x=u,split(rs(u),v-tr[ls(u)].siz-1,rs(u),y);
else y=u,split(ls(u),v,x,ls(u));
pushup(u);
}
int merge(int x,int y){
if(!x||!y) return x+y;
if(tr[x].pri<tr[y].pri){
if(tr[x].lazy) pushdown(x);
rs(x)=merge(rs(x),y);pushup(x);return x;
}
else{
if(tr[y].lazy) pushup(y); // <----
ls(y)=merge(x,ls(y));pushup(y);return y;
}
}
void rev(int l,int r){
int x,y,p;
split(root,r,x,y),split(x,l-1,x,p);
tr[p].lazy^=1;
root=merge(merge(x,p),y);
}
void print(int x){
if(tr[x].lazy) pushdown(x);
if(ls(x)) print(ls(x));
cout<<tr[x].val<<' ';
if(rs(x)) print(rs(x));
}
};
fhq tr;
signed main(){
ios::sync_with_stdio(0);
cin.tie(nullptr);
srand(time(0));
cin>>n>>m;
for(int i=1;i<=n;i++){
tr.newnode(i),tr.root=tr.merge(tr.root,i);
}
while(m--){
int l,r;
cin>>l>>r;
tr.rev(l,r);
}
tr.print(tr.root);
return 0;
}
```
by Lu_xZ @ 2024-08-02 00:54:51
@[Lu_xZ](/user/963559) ok
by _O_v_O_ @ 2024-08-02 10:30:14
草
by _O_v_O_ @ 2024-08-02 16:40:51