Language: C++

/*author: hyperion_1724
  date: 
*/

//Optional FAST

//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,fma,abm,mmx,avx,avx2,tune=native")

//Required Libraries

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>

//Required namespaces

using namespace std;
using namespace __gnu_pbds;

//Required defines

#define endl '\n'

#define READ(X) cin>>X;
#define READV(X) long long X; cin>>X;
#define READAR(A,N) long long A[N]; for(long long i=0;i<N;i++) {cin>>A[i];}
#define rz(A,N) A.resize(N);
#define sz(X) (long long)(X.size())
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define trav(x,A) for(auto &x:A)
#define FORI(a,b,c) for(long long a=b;a<c;a++)
#define FORD(a,b,c) for(long long a=b;a>c;a--)

//Required typedefs

typedef tree<long long,null_type,less<long long>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
typedef tree<long long,null_type,greater<long long>,rb_tree_tag,tree_order_statistics_node_update> ordered_set1;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<long long,long long> pll;
typedef vector<int> veci;
typedef vector<long long> vecl;

//Required Constants

const long long inf=(long long)1e18;
const long long MOD=(long long)(1e9+7);
const long long INIT=(long long)(1e6+1);

//Required Functions

ll power(ll x,ll y) 
{ 
    if (y == 0) 
        return 1; 
    ll p = power(x, y/2) % MOD; 
    p = (p * p) % MOD; 
  
    return (y%2 == 0)? p : (x * p) % MOD; 
}
ll modInverse(ll a) 
{ 
   return power(a,MOD-2); 
   
}

//Work

int main()
{
    #ifndef ONLINE_JUDGE
    if (fopen("INPUT.txt", "r"))
    {
        freopen ("INPUT.txt" , "r" , stdin);
        //freopen ("OUTPUT.txt" , "w" , stdout);
    }
    #endif
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    clock_t clk;
    clk = clock();
//-----------------------------------------------------------------------------------------------------------//

    string S;
    READ(S);
    READV(K);
    ll N=S.length();
    ll ans=0;
    ordered_set X;
    FORI(i,0,N)
    {
        if(S[i]!='0')
        {
            X.insert(i);
        }
    }
    if(K==1)
    {
        FORI(i,0,N)
        {
            if(i>0)
            {
                ans+=9;
            }
            else
            {
                ans+=(ll)S[i]-(ll)'0';
            }
        }
    }
    else if(K==2)
    {
        FORI(i,0,N)
        {
            FORI(j,i+1,N)
            {
                if(i>=1)
                {
                    ans+=9*9;
                }
                else
                {
                    
                    if(j>1 && S[1]!='0')
                    {
                        ans+=((ll)S[i]-(ll)'0')*9;
                    }
                    else if(j==1)
                    {
                        ans+=((ll)S[i]-(ll)'0'-1)*9;
                        ans+=((ll)S[j]-(ll)'0');
                    }
                }
            }
        }
    }
    else
    {
        FORI(i,0,N)
        {
            FORI(j,i+1,N)
            {
                FORI(k,j+1,N)
                {
                    if (i>=1)
                    {
                        ans+=9*9*9;
                    }
                    else
                    {
                        if(X.order_of_key(k)>=2)
                        {
                            ans+=((ll)S[i]-(ll)'0')*9*9;
                        }
                        else if(j==1)
                        {
                            ans+=((ll)S[i]-(ll)'0'-1)*9*9;
                            if((ll)S[j]-(ll)'0'>0)
                            {
                                if(k>2 && )
                                {
                                    ans+=((ll)S[j]-(ll)'0')*9;
                                }
                                else if(k==2)
                                {
                                    ans+=((ll)S[j]-(ll)'0'-1)*9;
                                    ans+=(ll)S[k]-(ll)'0';
                                }
                                
                            }
                        }
                        
                    }
                    
                }
            }
        }
    }
    cout<<ans<<endl;

//-----------------------------------------------------------------------------------------------------------//


    clk = clock() - clk;
    cerr << fixed << setprecision(6) << "Time: " << ((double)clk)/CLOCKS_PER_SEC << endl;

    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:169:43: error: expected primary-expression before ')' token
  169 |                                 if(k>2 && )
      |                                           ^