**hack**
```
3 4
1 2 3
2 1 2 3
1 1 3 2
2 3 3 1
3 1 1
```
正确答案是2，程序输出为5
原因：pushdownx的时候，不仅要修改儿子的lazyx，还需要清空儿子的lazy，对，清零。
亲测可以通过hack
by IamZZ @ 2023-10-09 14:46:57
谢谢
by kk_is_ethereal @ 2023-10-09 14:53:32
可是还是WA50pts诶 @[IamZZ](/user/552509)
by kk_is_ethereal @ 2023-10-09 14:56:35
```cpp
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline void read(int &x) {
x=0;
short flag=1;
char c=getchar();
while(c<'0'||c>'9'){
if(c=='-')flag = -1;
c=getchar();
}
while(c >= '0' && c <= '9'){
x=(x<<3)+(x<<1)+(c^48);
c=getchar();
}
x*=flag;
}
const int nul=1e18;
int n,a[200010],m;
struct tree{
int v,l,r,lazy,lazyx;
}t[10000000];
void build(int x,int l,int r){
t[x].l=l,t[x].r=r;
t[x].lazy=t[x].lazyx=nul;
if(l==r){
t[x].v=a[l];
return;
}
build(x<<1,l,(l+r)>>1);
build(x<<1|1,((l+r)>>1)+1,r);
t[x].v=max(t[x<<1].v,t[x<<1|1].v);
}
void push_down(int x){
t[x<<1].lazy+=t[x].lazy;
t[x<<1].lazy%=nul;
t[x<<1|1].lazy+=t[x].lazy;
t[x<<1|1].lazy%=nul;
t[x<<1].v+=t[x].lazy;
t[x<<1|1].v+=t[x].lazy;
t[x].lazy=nul;
}
void push_downx(int x){
t[x<<1].lazyx=t[x].lazyx;
t[x<<1].lazy=nul;
t[x<<1|1].lazyx=t[x].lazyx;
t[x<<1|1].lazy=nul;
t[x<<1].v=t[x].lazyx;
t[x<<1|1].v=t[x].lazyx;
t[x].lazyx=nul;
}
void update(int x){
if(t[x].lazyx!=nul)push_downx(x);
if(t[x].lazy!=nul)push_down(x);
}
void xiu(int x,int l,int r,int v){
if(l<=t[x].l&&t[x].r<=r){
t[x].v=v;
t[x].lazy=nul;
t[x].lazyx=v;
return;
}
update(x);
if(l<=t[x<<1].r)xiu(x<<1,l,r,v);
if(r>=t[x<<1|1].l)xiu(x<<1|1,l,r,v);
t[x].v=max(t[x<<1].v,t[x<<1|1].v);
}
void add(int x,int l,int r,int v){
if(l<=t[x].l&&t[x].r<=r){
t[x].v+=v;
if(t[x].lazyx!=nul)t[x].lazyx+=v;
else t[x].lazy=(t[x].lazy+v)%nul;
return;
}
update(x);
if(l<=t[x<<1].r)add(x<<1,l,r,v);
if(r>=t[x<<1|1].l)add(x<<1|1,l,r,v);
t[x].v=max(t[x<<1].v,t[x<<1|1].v);
}
int search(int x,int l,int r){
if(l<=t[x].l&&t[x].r<=r)return t[x].v;
update(x);
int s=-nul;
if(l<=t[x<<1].r)s=max(s,search(x<<1,l,r));
if(r>=t[x<<1|1].l)s=max(s,search(x<<1|1,l,r));
return s;
}
signed main(){
read(n),read(m);
for(int i=1;i<=n;i++)read(a[i]);
build(1,1,n);
for(int i=1;i<=m;i++){
int opt,l,r;
read(opt),read(l),read(r);
if(opt==1){
int x;
read(x);
xiu(1,l,r,x);
}
if(opt==2){
int x;
read(x);
add(1,l,r,x);
}
if(opt==3){
printf("%lld\n",search(1,l,r));
}
}
return 0;
}
```
by kk_is_ethereal @ 2023-10-09 14:57:26
过了
by kk_is_ethereal @ 2023-10-09 16:10:31
@[kk_is_ethereal](/user/726368)
add的时候不要修改lazyx（乐
by IamZZ @ 2023-10-09 16:16:32
@[IamZZ](/user/552509) 已经过了谢谢
by kk_is_ethereal @ 2023-10-09 16:26:02
@[kk_is_ethereal](/user/726368) OK
by IamZZ @ 2023-10-09 16:28:30