实现的功能：将序列区间反转，并维护
详见BZOJ3223
var
i,j,k,l,m,n,head,a1,a2:longint;
s1:ansistring;
a,b,c,d,fat,lef,rig:array[..] of longint;
procedure swap(var x,y:longint);inline;
var z:longint;
begin
z:=x;x:=y;y:=z;
end; procedure ext(x:longint);inline;
begin
if (x=) then exit;
if c[x]= then exit;
swap(lef[x],rig[x]);
c[x]:=;
c[lef[x]]:=-c[lef[x]];
c[rig[x]]:=-c[rig[x]];
c[]:=;
end;
procedure rt(x:longint);inline;
var f,l:longint;
begin
if x= then exit;
ext(x);
if lef[x]= then exit;
ext(lef[x]);
f:=x;l:=lef[x];
b[lef[x]]:=b[x];
b[x]:=b[rig[x]]++b[rig[l]];
lef[x]:=rig[l];
fat[rig[l]]:=x;
rig[l]:=x;
fat[l]:=fat[x];
fat[x]:=l;
if rig[fat[l]]=x then rig[fat[l]]:=l;
if lef[fat[l]]=x then lef[fat[l]]:=l;
fat[]:=;
end;
procedure lt(x:longint);inline;
var f,r:longint;
begin
if x= then exit;
ext(x);if rig[x]= then exit;
ext(rig[x]);
f:=x;r:=rig[x];
b[rig[x]]:=b[x];
b[x]:=+b[lef[x]]+b[lef[r]];
rig[x]:=lef[r];
fat[lef[r]]:=x;
lef[r]:=x;
fat[r]:=fat[x];
fat[x]:=r;
if rig[fat[r]]=x then rig[fat[r]]:=r;
if lef[fat[r]]=x then lef[fat[r]]:=r;
fat[]:=;
end;
procedure ins(x,y:longint);inline;
begin
if a[y]<a[x] then
begin
if lef[x]= then
begin
lef[x]:=y;
fat[y]:=x;
end
else ins(lef[x],y);
end
else
begin
if rig[x]= then
begin
rig[x]:=y;
fat[y]:=x;
end
else ins(rig[x],y);
end;
b[x]:=+b[lef[x]]+b[rig[x]];
end;
procedure up2(var x:longint);inline;
begin
if (fat[x]=) or (x=) then exit;
if lef[fat[x]]=x then
begin
if lef[fat[fat[x]]]=fat[x] then
begin
rt(fat[fat[x]]);
rt(fat[x]);
end
else
begin
rt(fat[x]);
lt(fat[x]);
end;
end
else
begin
if rig[fat[fat[x]]]=fat[x] then
begin
lt(fat[fat[x]]);
lt(fat[x]);
end
else
begin
lt(fat[x]);
rt(fat[x]);
end;
end;
end;
procedure up1(x:longint);inline;
begin
if (x=) or (fat[x]=) then exit;
if lef[fat[x]]=x then rt(fat[x]) else lt(fat[x]);
end;
procedure splay(x:longint);inline;
begin
if (x=) or (fat[x]=) then exit;
while fat[fat[x]]> do
up2(x);
if fat[x]> then up2(x);
head:=x;
end;
procedure splay2(x:longint);inline;
begin
if (x=) or (fat[x]=) then exit;
while fat[fat[fat[x]]]> do
up2(x);
if fat[fat[x]]> then up1(x);
end;
function getrank(x,y:longint):longint;inline;
begin
if (x=) then exit();
ext(x);
if (b[lef[x]]+)=y then exit(x);
if (b[lef[x]]+)>y then exit(getrank(lef[x],y)) else exit(getrank(rig[x],y--b[lef[x]]));
end;
procedure turn(x,y:longint);inline;
var a1,a2:longint;
begin
if (x=) and (y=n) then
c[head]:=-c[head]
else
begin
if (x=) then
begin
a1:=getrank(head,y+);
splay(a1);
ext(a1);
c[lef[a1]]:=-c[lef[a1]];
end
else
begin
if (y=n) then
begin
a2:=getrank(head,x-);
splay(a2);
ext(a2);
c[rig[a2]]:=-c[rig[a2]];
end
else
begin
a1:=getrank(head,x-);
a2:=getrank(head,y+);
splay(a2);splay2(a1);
ext(a2);ext(a1);
c[rig[a1]]:=-c[rig[a1]];
end;
end;
end;
end;
function showoff(x:longint):ansistring;inline;
var s1:ansistring;
begin
if x= then exit('');
ext(x);
str(x,s1);
exit(showoff(lef[x])+s1+' '+showoff(rig[x]));
end;
begin
readln(n,m);
for i:= to n do
begin
a[i]:=i;c[i]:=;b[i]:=;
end;
head:=;
for i:= to n do
begin
ins(head,i);
splay(random(i)+);
end;
for i:= to m do
begin
readln(a1,a2);
turn(a1,a2);
end;
s1:=showoff(head);
writeln(s1);
readln;
end.