```#include<bits/stdc++.h>
using namespace std;
#define int long long 
int digit[15];
int dp[15][105][2][2];
int n,k;
int dfs(int pos,int sum,bool limit,bool lead){
    if (pos == 0) {
        return !lead && sum <= k;
    }
    if (dp[pos][sum][limit][lead] != -1)
        return dp[pos][sum][limit][lead];
    	int ans = 0; 
    int up = limit ? digit[pos] : 9;
    for (int i = 0; i <= up; ++i) {
        bool new_limit = limit && (i == up);
        bool new_lead = lead && (i == 0);
        int new_sum = sum;
        if(!new_lead) new_sum += i; 
        if(new_sum > k) continue;
        ans += dfs(pos-1, new_sum, new_limit, new_lead);
    }
    return dp[pos][sum][limit][lead] = ans;
}
int count(int len){
	int x=0;
	for(int i=0;i<len;i++) x = x*10 +9;
    int cnt = 0;
    while(x){
        digit[++cnt] = x%10;
        x /=10;
    }
    memset(dp,-1,sizeof(dp));
    return dfs(cnt,0,1,1);
}
signed main(){
	int T;
	cin>>T;
	while(T--){
		cin>>n>>k;
		cout<<count(n)<<endl;
	}
}

language

#include<bits/stdc++.h> using namespace std; #define int long long int digit[15]; int dp[15][105][2][2]; int n,k; int dfs(int pos,int sum,bool limit,bool lead){ if (pos == 0) { return !lead && sum <= k; } if (dp[pos][sum][limit][lead] != -1) return dp[pos][sum][limit][lead]; int ans = 0; int up = limit ? digit[pos] : 9; for (int i = 0; i <= up; ++i) { bool new_limit = limit && (i == up); bool new_lead = lead && (i == 0); int new_sum = sum; if(!new_lead) new_sum += i; if(new_sum > k) continue; ans += dfs(pos-1, new_sum, new_limit, new_lead); } return dp[pos][sum][limit][lead] = ans; } int count(int len){ int x=0; for(int i=0;i<len;i++) x = x*10 +9; int cnt = 0; while(x){ digit[++cnt] = x%10; x /=10; } memset(dp,-1,sizeof(dp)); return dfs(cnt,0,1,1); } signed main(){ int T; cin>>T; while(T--){ cin>>n>>k; cout<<count(n)<<endl; } } ``

```language

```#include<bits/stdc++.h>
using namespace std;
#define int long long
int digit[20];
int dp[20][2][2];
int x;
int dfs(int pos, bool limit, bool lead)
{
    if(pos==0)
        return 1;
    if(dp[pos][limit][lead]!=-1)
        return dp[pos][limit][lead];
    int ans=0;
    int up=limit? digit[pos]:9;
    for(int i=0;i<=up;i++)
    {
        if(i==x) continue;
        bool new_limit=limit&&(i==up);
        bool new_lead=lead&&(i==0);
        if(lead&&i==0)
            ans+=dfs(pos-1,new_limit,new_lead);
        else
            ans+=dfs(pos-1,new_limit,new_lead);
    }
    return dp[pos][limit][lead]=ans;
}

int count(int n)
{
    if(n<0) return 0;
    int cnt=0;
    int tmp=n;
    while(tmp)
    {
        digit[++cnt]=tmp%10;
        tmp/=10;
    }
    memset(dp,-1,sizeof(dp));
    return dfs(cnt,1,1);
}

signed main()
{
    int T;
    cin>>T;
    while(T--)
    {
        int n;
        cin>>n>>x;
        cout<<count(n)<<endl;
    }
    return 0;
}