思路:记忆化搜索
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <cmath>
#include <ctime>
#include <vector>
#include <cstdio>
#include <cctype>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;
#define INF 0x3f3f3f3f
#define inf -0x3f3f3f3f
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define mem0(a) memset(a,0,sizeof(a))
#define mem1(a) memset(a,-1,sizeof(a))
#define mem(a, b) memset(a, b, sizeof(a))
typedef long long ll;
ll dp[21][21][2001];
ll bit[21];
ll dfs(ll pos,ll zhidian,ll pre,ll lim){
if(pos<=0)
return pre==0;
if(pre<0)
return 0;
if(!lim&&dp[pos][zhidian][pre]!=-1)
return dp[pos][zhidian][pre];
ll num=lim ? bit[pos]:9;
ll ans=0;
for(ll i=0;i<=num;i++){
ans+=dfs(pos-1,zhidian,pre+(pos-zhidian)*i,lim&&(i==num));
}
if(!lim)
dp[pos][zhidian][pre]=ans;
return ans;
}
ll solve(ll n){
ll len=0;
while(n){
bit[++len]=n%10;
n/=10;
}
ll ans=0;
for(ll i=1;i<=len;i++)
ans+=dfs(len,i,0,1);
return ans-(len-1);
}
int main(){
ll t;
ll n,m;
scanf("%d",&t);
mem1(dp);
while(t--){
scanf("%lld%lld",&n,&m);
printf("%lld\n",solve(m)-solve(n-1));
}
return 0;
}