RT，悬赏2关注

#include <bits/stdc++.h>
#define int long long
#define R register 
using namespace std;
const int N=1e6+5;
const int INF=1e18;
struct node{
	int l,r;
	int val;
	int tag_add,tag_cover;
}tr[N*10]; 
int a[N];


inline void cover_down(int p){
	int ls=p*2;
	int rs=p*2+1;
	if(tr[p].tag_cover==INF) return;
	tr[ls].val=tr[ls].tag_cover=tr[p].tag_cover;
	tr[ls].tag_add=0;
	tr[rs].val=tr[rs].tag_cover=tr[p].tag_cover;
	tr[rs].tag_add=0;
	tr[p].tag_cover=INF;
	return;
}

inline void add_down(int p){
	int ls=p*2;
	int rs=p*2+1;
	if(tr[p].tag_add==0) return;
//	cover_down(p);
	tr[ls].val+=tr[p].tag_add;
	tr[ls].tag_add+=tr[p].tag_add;
	tr[rs].val+=tr[p].tag_add;
	tr[rs].tag_add+=tr[p].tag_add;
	tr[p].tag_add=0;
	return;
}

inline void push_up(int p){
	int ls=p*2;
	int rs=p*2+1;
	tr[p].val=max(tr[ls].val,tr[rs].val);
	return;
}

inline void build(int p,int l,int r){
	tr[p].l=l;
	tr[p].r=r;
	if(l==r){
		tr[p].val=a[l];
		tr[p].tag_cover=INF;
		tr[p].tag_add=0;
		return;
	}
	int mid=(l+r)/2;
	build(p*2,l,mid);
	build(p*2+1,mid+1,r);
	push_up(p);
	return;
}

inline void upd_add(int p,int ql,int qr,int v){
	
	int l=tr[p].l;
	int r=tr[p].r;
//	cout<<"add: "<<l<<' '<<r<<' '<<v<<endl;
	int ls=p*2;
	int rs=p*2+1;
	if(ql<=l && r<=qr){
//		cout<<"find! "<<l<<' '<<r<<endl;
		cover_down(p);
		tr[p].tag_add+=v;
		tr[p].val+=v;
		return;
	}
	int mid=(l+r)/2;
	cover_down(p);
	add_down(p);
	
	if(ql<=mid){
		upd_add(ls,ql,qr,v);
	}
	if(mid+1<=qr){
		upd_add(rs,ql,qr,v);
	}
	push_up(p);
	return;
}

inline void upd_cover(int p,int ql,int qr,int v){
	int l=tr[p].l;
	int r=tr[p].r;
//	cout<<"cover: "<<l<<' '<<r<<' '<<v<<endl;
	int ls=p*2;
	int rs=p*2+1;
	if(ql<=l && r<=qr){
//		cout<<"find! "<<l<<' '<<r<<endl;
		tr[p].tag_cover=v;
		tr[p].val=v;
		tr[p].tag_add=0;
		return;
	}
	int mid=(l+r)/2;
	cover_down(p);
	add_down(p);
	
	if(ql<=mid){
		upd_cover(ls,ql,qr,v);
	}
	if(mid+1<=qr){
		upd_cover(rs,ql,qr,v);
	}
	push_up(p);
	return;
}

inline int query(int p,int ql,int qr){
	int l=tr[p].l;
	int r=tr[p].r;
	int ls=p*2;
	int rs=p*2+1;
	if(ql<=l && r<=qr){
		return tr[p].val;
	}
	cover_down(p);
	add_down(p);
	int mid=(l+r)/2;
	int res=-INF;
	if(ql<=mid){
		res=max(res,query(ls,ql,qr));
	}
	if(mid+1<=r){
		res=max(res,query(rs,ql,qr));
	}
	return res;
}
int n,q;
signed main() {
//	freopen("P1253_5.in","r",stdin);
//	freopen("P1253_5.out","w",stdout);
	scanf("%lld%lld",&n,&q);
	for(int i=1;i<=n;i++){
		scanf("%lld",&a[i]);
	}
	build(1,1,n);
	for(R int i=1;i<=n*4;i++){
		tr[i].tag_cover=INF;
	}
	
	for(R int i=1;i<=q;i++){
		int opt,l,r,x;
		scanf("%lld",&opt);
		if(opt==1){
			scanf("%lld%lld%lld",&l,&r,&x);
			upd_cover(1,l,r,x);
		}
		else if(opt==2){
			scanf("%lld%lld%lld",&l,&r,&x);
			upd_add(1,l,r,x);
		}
		else{
			scanf("%lld%lld",&l,&r);
			printf("%lld\n",query(1,l,r));
		}
	}
	
	return 0;
}

感觉复杂度是对的啊……

这就是大常数选手吗……