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平衡樹板子題。

直接fhqtreap打區間標記就行了。

程式碼：

#include<bits/stdc++.h>
#define N 50005
using namespace std;
typedef pair<int,int> res;
inline int read(){
    int ans=0,w=1;
    char ch=getchar();
    while(!isdigit(ch)){if(ch=='-')w=-1;ch=getchar();}
    while(isdigit(ch))ans=(ans<<3)+(ans<<1)+(ch^48),ch=getchar();
    return ans*w;
}
int n,m,cnt=0,rt=0,val[N],son[N][2],siz[N],rev[N],rd[N],mx[N],add[N];
inline void pushup(int p){
    siz[p]=siz[son[p][0]]+siz[son[p][1]]+1;
    mx[p]=val[p];
    if(son[p][0])mx[p]=max(mx[p],mx[son[p][0]]);
    if(son[p][1])mx[p]=max(mx[p],mx[son[p][1]]);
}
inline int newnode(){
    siz[++cnt]=1,son[cnt][0]=son[cnt][1]=0;
    val[cnt]=rev[cnt]=add[N]=mx[cnt]=0,rd[cnt]=rand();
    return cnt;
}
inline void pushadd(int p,int v){add[p]+=v,mx[p]+=v,val[p]+=v;}
inline void pushrev(int p){swap(son[p][0],son[p][1]),rev[p]^=1;}
inline void pushdown(int p){
    if(rev[p]){
        if(son[p][0])pushrev(son[p][0]);
        if(son[p][1])pushrev(son[p][1]);
        rev[p]=0;
    }
    if(add[p]){
        if(son[p][0])pushadd(son[p][0],add[p]);
        if(son[p][1])pushadd(son[p][1],add[p]);
        add[p]=0;
    }
}
inline int merge(int a,int b){
    if(!a||!b)return a+b;
    pushdown(a),pushdown(b);
    if(rd[a]>=rd[b]){son[a][1]=merge(son[a][1],b),pushup(a);return a;}
    son[b][0]=merge(a,son[b][0]),pushup(b);return b;
}
inline res split(int p,int k){
    if(!p)return res(0,0);
    res tmp,ans;
    pushdown(p);
    if(siz[son[p][0]]>=k){
        tmp=split(son[p][0],k);
        ans.first=tmp.first,son[p][0]=tmp.second,pushup(ans.second=p);
        return ans;
    }
    tmp=split(son[p][1],k-siz[son[p][0]]-1);
    ans.second=tmp.second,son[p][1]=tmp.first,pushup(ans.first=p);
    return ans;
}
inline int rank(int p,int v){
    if(!p)return 0;
    pushdown(p);
    if(val[p]>v)return rank(son[p][0],v);
    return rank(son[p][1],v)+siz[son[p][0]]+1;
}
inline void update(){
    int l=read(),r=read(),v=read();
    res x=split(rt,r),y=split(x.first,l-1);
    pushadd(y.second,v);
    rt=merge(merge(y.first,y.second),x.second);
}
inline void reverse(){
    int l=read(),r=read();
    res x=split(rt,r),y=split(x.first,l-1);
    pushrev(y.second);
    rt=merge(merge(y.first,y.second),x.second);
}
inline void query(){
    int l=read(),r=read();
    res x=split(rt,r),y=split(x.first,l-1);
    printf("%d\n",mx[y.second]);
    rt=merge(merge(y.first,y.second),x.second);
}
inline void ins(){
    int p=newnode();
    rt=merge(rt,p);
}
int main(){
    n=read(),m=read();
    for(int i=1;i<=n;++i)ins();
    while(m--){
        int op=read();
        if(op==1)update();
        if(op==2)reverse();
        if(op==3)query();
    }
    return 0;
}