裸的splay，只需要注意 max[-1]:=-maxlongint 就行了，否则在update的时候子节点的
max值会在max[-1]里选
/**************************************************************
Problem: 1251
User: BLADEVIL
Language: Pascal
Result: Accepted
Time:16008 ms
Memory:3448 kb
****************************************************************/
//By BLADEVIL
const
sroot =-1;
var
n, m :longint;
i :longint;
a, father :array[-1..100010] of longint;
k, l, r, v :longint;
root :longint;
max, size, tree :array[-1..100010] of longint;
val :array[-1..100010] of longint;
flag :array[-1..100010] of boolean;
son :array[-1..100010,0..1] of longint;
procedure swap(var a,b:longint);
var
c :longint;
begin
c:=a; a:=b; b:=c;
end;
function get_max(a,b:longint):longint;
begin
if a>b then exit(a) else exit(b);
end;
procedure renew_add(x,v:longint);
begin
inc(tree[x],v); inc(val[x],v); inc(max[x],v);
end;
procedure renew_reverse(x:longint);
begin
swap(son[x,1],son[x,0]);
flag[x]:=not flag[x];
end;
procedure update(x:longint);
begin
//if x=sroot then exit;
max[x]:=get_max(tree[x],get_max(max[son[x,1]],max[son[x,0]]));
size[x]:=size[son[x,1]]+size[son[x,0]]+1;
end;
function build(l,r:longint):longint;
var
mid :longint;
begin
mid:=(r+l) div 2;
build:=mid;
tree[mid]:=a[mid];
if l+1<=mid then
begin
son[mid,0]:=build(l,mid-1);
father[son[mid,0]]:=mid;
end;
if mid<=r-1 then
begin
son[mid,1]:=build(mid+1,r);
father[son[mid,1]]:=mid;
end;
update(mid);
end;
procedure push_down(x:longint);
var
l, r :longint;
begin
l:=son[x,0]; r:=son[x,1];
if flag[x] then
begin
if l<>-1 then renew_reverse(l);
if r<>-1 then renew_reverse(r);
flag[x]:=false;
end;
if val[x]<>0 then
begin
if l<>-1 then renew_add(l,val[x]);
if r<>-1 then renew_add(r,val[x]);
val[x]:=0;
end;
end;
function find(x:longint):longint;
var
t :longint;
begin
t:=root;
while true do
begin
push_down(t);
if size[son[t,0]]+1=x then exit(t);
if size[son[t,0]]+1>x then t:=son[t,0] else
begin
dec(x,size[son[t,0]]+1);
t:=son[t,1];
end;
end;
end;
procedure rotate(x,y:longint);
var
f :longint;
begin
push_down(x);
f:=father[x];
father[son[x,y xor 1]]:=f;
son[f,y]:=son[x,y xor 1];
if f=root then root:=x else
if f=son[father[f],0] then
son[father[f],0]:=x else
son[father[f],1]:=x;
father[x]:=father[f];
father[f]:=x;
son[x,y xor 1]:=f;
update(f);
update(x);
end;
procedure splay(x,y:longint);
var
u, v :longint;
begin
while father[x]<>y do
begin
if father[father[x]]=y then
rotate(x,ord(x=son[father[x],1])) else
begin
if son[father[x],0]=x then u:=1 else u:=-1;
if son[father[father[x]],0]=father[x] then v:=1 else v:=-1;
if u*v=1 then
begin
rotate(father[x],ord(x=son[father[x],1]));
rotate(x,ord(x=son[father[x],1]));
end else
begin
rotate(x,ord(x=son[father[x],1]));
rotate(x,ord(x=son[father[x],1]));
end;
end;
end;
update(x);
end;
procedure add(l,r,v:longint);
var
p :longint;
begin
p:=find(l);splay(p,sroot);
p:=find(r+2);splay(p,root);
p:=son[son[root,1],0];
renew_add(p,v);
end;
procedure reverse(l,r:longint);
var
p :longint;
begin
p:=find(l);splay(p,sroot);
p:=find(r+2);splay(p,root);
p:=son[son[root,1],0];
renew_reverse(p);
end;
function ask_max(l,r:longint):longint;
var
p :longint;
begin
p:=find(l); splay(p,sroot);
p:=find(r+2); splay(p,root);
p:=son[son[root,1],0];
ask_max:=max[p];
end;
begin
fillchar(son,sizeof(son),255);
read(n,m);
max[-1]:=-maxlongint;
for i:=1 to n do a[i]:=0;
inc(n);
root:=build(0,n);
father[root]:=sroot;
for i:=1 to m do
begin
read(k);
if k=1 then
begin
read(l,r,v);
add(l,r,v);
end else
begin
read(l,r);
if k=2 then
reverse(l,r) else
writeln(ask_max(l,r));
end;
end;
end.