传送门

题意：

思路：

平衡树裸题，直接维护俩$lazy$就行了。
需要注意的是，只有儿子节点存在的时候才能更新，不然更新到$0$号节点之后，给$0$号点加上了奇怪的值，在$pushup$的时候如果儿子不存在就拿$0$号节点更新答案了，所以需要特判以下。

// Problem: P4146 序列终结者
// Contest: Luogu
// URL: https://www.luogu.com.cn/problem/P4146
// Memory Limit: 125 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)//#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4.1,sse4.2,avx,avx2,popcnt,tune=native")
//#pragma GCC optimize(2)
#include<cstdio>
#include<iostream>
#include<string>
#include<cstring>
#include<map>
#include<cmath>
#include<cctype>
#include<vector>
#include<set>
#include<queue>
#include<algorithm>
#include<sstream>
#include<ctime>
#include<cstdlib>
#define X first
#define Y second
#define L (u<<1)
#define R (u<<1|1)
#define pb push_back
#define mk make_pair
#define Mid (tr[u].l+tr[u].r>>1)
#define Len(u) (tr[u].r-tr[u].l+1)
#define random(a,b) ((a)+rand()%((b)-(a)+1))
#define db puts("---")
using namespace std;//void rd_cre() { freopen("d://dp//data.txt","w",stdout); srand(time(NULL)); }
//void rd_ac() { freopen("d://dp//data.txt","r",stdin); freopen("d://dp//AC.txt","w",stdout); }
//void rd_wa() { freopen("d://dp//data.txt","r",stdin); freopen("d://dp//WA.txt","w",stdout); }typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int,int> PII;const int N=1000010,mod=1e9+7,INF=0x3f3f3f3f;
const double eps=1e-6;int n,m;
int root,x,y,z,tot;
struct Node {int l,r;int val,mx,rank,size,lazy1,lazy2;
}tr[N];void pushup(int u) {tr[u].size=tr[tr[u].l].size+tr[tr[u].r].size+1;tr[u].mx=tr[u].val;if(tr[u].l) tr[u].mx=max(tr[u].mx,tr[tr[u].l].mx);if(tr[u].r) tr[u].mx=max(tr[u].mx,tr[tr[u].r].mx);
}void pushdown(int u) {if(tr[u].lazy1) {tr[u].lazy1=0;swap(tr[u].l,tr[u].r);if(tr[u].l) tr[tr[u].l].lazy1^=1;if(tr[u].r) tr[tr[u].r].lazy1^=1;}if(tr[u].lazy2) {int lazy=tr[u].lazy2; tr[u].lazy2=0;if(tr[u].l) tr[tr[u].l].lazy2+=lazy,tr[tr[u].l].val+=lazy,tr[tr[u].l].mx+=lazy;if(tr[u].r) tr[tr[u].r].lazy2+=lazy,tr[tr[u].r].val+=lazy,tr[tr[u].r].mx+=lazy;}
}int newnode(int v) {int u=++tot;tr[u].l=tr[u].r=0;tr[u].rank=rand(); tr[u].lazy1=tr[u].lazy2=0;tr[u].size=1; tr[u].val=0; tr[u].mx=0;return u;
}void split(int u,int k,int &x,int &y) {if(!u) { x=y=0; return; }pushdown(u);if(k<=tr[tr[u].l].size) y=u,split(tr[u].l,k,x,tr[u].l);else x=u,split(tr[u].r,k-tr[tr[u].l].size-1,tr[u].r,y);pushup(u);
}int merge(int u,int v) {if(!u||!v) return u+v;if(tr[u].rank<tr[v].rank) {pushdown(u);tr[u].r=merge(tr[u].r,v);pushup(u);return u;} else {pushdown(v);tr[v].l=merge(u,tr[v].l);pushup(v);return v;}
}void dfs(int u) {if(!u) return;pushdown(u);dfs(tr[u].l);printf("%d %d\n",tr[u].val,tr[u].mx);dfs(tr[u].r);
}int main()
{
//	ios::sync_with_stdio(false);
//	cin.tie(0);scanf("%d%d",&n,&m);for(int i=1;i<=n;i++) {root=merge(root,newnode(0));} while(m--) {int op,l,r; scanf("%d%d%d",&op,&l,&r);if(op==1) {int v; scanf("%d",&v);split(root,r,x,z);split(x,l-1,x,y);tr[y].lazy2+=v; tr[y].val+=v; tr[y].mx+=v;root=merge(merge(x,y),z);} else if(op==2) {split(root,r,x,z);split(x,l-1,x,y);tr[y].lazy1^=1;root=merge(merge(x,y),z);} else {split(root,r,x,z);split(x,l-1,x,y);printf("%d\n",tr[y].mx);root=merge(merge(x,y),z);}}return 0;
}
/**/