6分，求佬调

#include<iostream>
#include<climits>
using namespace std;
using ll=long long;
const int N=1e6+9;
ll a[N],t[N*4],lazy1[N*4];
bool lazy2[N*4]; 
int op,l,r,x,n,q;
inline int lc(int p){return p<<1;}
inline int rc(int p){return p<<1|1;}
void pushUp(int p){
    t[p]=max(t[lc(p)],t[rc(p)]);
}
void buildTree(int p,int l,int r){
    if(l==r){
        t[p]=a[l];
        return;
    }
    int mid=(l+r)>>1;
    buildTree(lc(p),l,mid);
    buildTree(rc(p),mid+1,r);
    pushUp(p);
}
void movetag(int p,ll c){
    t[p]+=c;
    lazy1[p]+=c;
}
void change(int p,ll c){
    lazy2[p]=1;
    lazy1[p]=0;
    t[p]=c;
}
void pushDown(int p){
    if(lazy2[p]){
        change(lc(p),t[p]);
        change(rc(p),t[p]);
        lazy2[p]=0;
    }
    else{
        movetag(lc(p),lazy1[p]);
        movetag(rc(p),lazy1[p]);
        lazy1[p]=0;
    }
}
void update(int p,int l,int r,int ql,int qr,ll c){
    if(ql<=l&&r<=qr){
        t[p]=c;
        lazy1[p]=0;
        lazy2[p]=1;
        return ;
    }
    pushDown(p);
    int mid=(l+r)>>1;
    if(ql<=mid){
        update(lc(p),l,mid,ql,qr,c);
    }
    if(mid<qr){
        update(rc(p),mid+1,r,ql,qr,c);
    }
    pushUp(p);
}
void add(int p,int l,int r,int ql,int qr,ll c){
    if(ql<=l&&r<=qr){
        if(lazy2[p]){
            pushDown(p);
        }
        t[p]+=c;
        lazy1[p]+=c;
        return ;
    }
    pushDown(p);
    int mid=(l+r)>>1;
    if(ql<=mid){
        add(lc(p),l,mid,ql,qr,c);
    }
    if(mid<qr){
        add(rc(p),mid+1,r,ql,qr,c);
    }
    pushUp(p);
}
ll query(int p,int l,int r,int ql,int qr){
    if(ql<=l&&r<=qr){
        return t[p];
    }
    pushDown(p);
    int mid=(l+r)>>1;
    ll ans=LLONG_MIN;
    if(ql<=mid){
        ans=max(ans,query(lc(p),l,mid,ql,qr));
    }
    if(mid<qr){
        ans=max(ans,query(rc(p),mid+1,r,ql,qr));
    }
    return ans;
}
int main(){
    ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
    cin>>n>>q;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    buildTree(1,1,N);
    while(q--){
        cin>>op;
        switch(op){
            case 1:
                cin>>l>>r>>x;
                update(1,1,N,l,r,x);
                break;
            case 2:
                cin>>l>>r>>x;
                add(1,1,N,l,r,x);
                break;
            default:
                cin>>l>>r;
                cout<<query(1,1,N,l,r)<<endl;
        }
    }
    return 0;
}