Digit (数位DP）

 1 const maxn=13;
 2 var T:longint;
 3     a:array[0..maxn] of longint;
 4     f:array[0..maxn,0..maxn,0..maxn,-9..9,0..9,0..1,0..1] of int64;
 5 function max(a,b:longint):longint; inline;
 6 begin
 7     if a>b then exit(a) else exit(b);
 8 end;
 9 function dfs(now,ml,l,d,pre,st,lim:longint):int64;
10 var mx,i:longint; sum:int64;
11 begin
12 //now 第now位
13 //ml 最长长度
14 //l 当前长度
15 //d 公差为d
16 //st  有无前导0
17 //pre 上一位是多少
18 //lim 是否达到上限
19     if f[now,ml,l,d,pre,st,lim]>0 then exit(f[now,ml,l,d,pre,st,lim]);
20     if now=0 then exit(ml);
21     if lim=1 then mx:=a[now] else mx:=9;
22     sum:=0;
23     for i:=0 to mx do
24         if st=1 then
25             if i=0 then
26                 sum:=sum+dfs(now-1,0,0,i-pre,i,1,lim and ord(i=mx))
27             else
28                 sum:=sum+dfs(now-1,max(ml,l+1),l+1,i-pre,i,0,lim and ord(i=mx))
29         else
30             if i-pre=d then
31                 sum:=sum+dfs(now-1,max(ml,l+1),l+1,i-pre,i,0,lim and ord(i=mx))
32             else
33                 sum:=sum+dfs(now-1,max(ml,2),2,i-pre,i,0,lim and ord(i=mx));
34     f[now,ml,l,d,pre,st,lim]:=sum;
35     exit(sum);
36 end;
37 function calc(x:int64):int64;
38 var len:longint;
39 begin
40     fillchar(f,sizeof(f),0);
41     len:=0;
42     while x>0 do
43     begin
44         inc(len);
45         a[len]:=x mod 10;
46         x:=x div 10;
47     end;
48     exit(dfs(len,0,0,0,0,1,1));
49 end;
50 procedure main;
51 var l,r:int64;
52 begin
53     readln(l,r);
54     writeln(calc(r)-calc(l-1));
55 end;
56 begin
57     readln(T);
58     while T>0 do begin main; dec(T); end;
59 
60 end.