Digital skills dp

A strange thing

Positive and negative can dp !:
normal digital dp we are descending, in such a way to ensure that a given number is less than ->

ll n;
int num[N],l;
ll dp[];
ll dfs(int p,int lim){
    if(p==0) return 1;
    if(!lim&&~dp[]) return dp[];
    int Uplim=lim?num[p]:9;
    ll res=0;
    for(int i=0;i<=Uplim;i++) {
        res+=dfs(p-1,lim&&(i==Uplim));
    }
    if(!lim) dp[]=res;
    return res;
}

int main(){
    scanf("%lld",&n);
    while(n) num[++l]=n%10,n/=10;
    printf("%lld\n",dfs(l,1));
}

However, from low to high it should be like this:

ll n;
int num[N],l;
ll dp[];
ll dfs(int p,int fl){
    if(p==l+1) return fl;
    if(~dp[]) return dp[];
    ll res=0;
    for(int i=0;i<10;i++) {
        res+=dfs(p+1,i<num[p]||(i==num[p]&&fl));
    }
    return dp[]=res;
}

int main(){
    scanf("%lld",&n);
    while(n) num[++l]=n%10,n/=10;
    printf("%lld\n",dfs(1,1));
}

In some special cases this can eliminate some of the aftereffect and cumbersome steps