Language: C++

#include <iostream>
 
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <algorithm>
#define ll long long
#define M 998244353
const int x=300005;
using namespace std;
ll fac[x]={1,1},inv[x]={1,1},f[x]={1,1};
ll C(ll a,ll b){
    if(b>a)return 0;
    return fac[a]*inv[b]%M*inv[a-b]%M;
}
void init(){
    for(int i=2;i<x;i++){
        fac[i]=fac[i-1]*i%M;
        f[i]=(M-M/i)*f[M%i]%M;
        inv[i]=inv[i-1]*f[i]%M;
    }
}
int main()
{
    ll N,A,B,K;
    cin>>N>>A>>B>>K;
    init();
    ll i;long long j,sum,ans=0;
    for(i=0;i<=N;i++){
        sum=i*A;
            if((K-sum)>=0&&(K-sum)%B==0){
                j=(K-sum)/B;
                if(j>N) continue;
                ans=ans+C(N,i)*C(N,j);
                ans%=M;
            }
    }
    cout<<ans<<endl;
    return 0;
}//代码中的组合数算法是别人提交的代码中的

Compiler output:
a.cc:14:1: error: extended character   is not valid in an identifier
   14 |     if(b>a)return 0;
      | ^
a.cc:14:1: error: extended character   is not valid in an identifier
a.cc:14:1: error: extended character   is not valid in an identifier
a.cc:15:1: error: extended character   is not valid in an identifier
   15 |     return fac[a]*inv[b]%M*inv[a-b]%M;
      | ^
a.cc:15:1: error: extended character   is not valid in an identifier
a.cc:15:1: error: extended character   is not valid in an identifier
a.cc:18:1: error: extended character   is not valid in an identifier
   18 |     for(int i=2;i<x;i++){
      | ^
a.cc:18:1: error: extended character   is not valid in an identifier
a.cc:18:1: error: extended character   is not valid in an identifier
a.cc:19:1: error: extended character   is not valid in an identifier
   19 |         fac[i]=fac[i-1]*i%M;
      | ^
a.cc:19:1: error: extended character   is not valid in an identifier
a.cc:19:1: error: extended character   is not valid in an identifier
a.cc:19:1: error: extended character   is not valid in an identifier
a.cc:19:1: error: extended character   is not valid in an identifier
a.cc:19:1: error: extended character   is not valid in an identifier
a.cc:19:1: error: extended character   is not valid in an identifier
a.cc:20:1: error: extended character   is not valid in an identifier
   20 |         f[i]=(M-M/i)*f[M%i]%M;
      | ^
a.cc:20:1: error: extended character   is not valid in an identifier
a.cc:20:1: error: extended character   is not valid in an identifier
a.cc:20:1: error: extended character   is not valid in an identifier
a.cc:20:1: error: extended character   is not valid in an identifier
a.cc:20:1: error: extended character   is not valid in an identifier
a.cc:20:1: error: extended character   is not valid in an identifier
a.cc:21:1: error: extended character   is not valid in an identifier
   21 |         inv[i]=inv[i-1]*f[i]%M;
      | ^
a.cc:21:1: error: extended character   is not valid in an identifier
a.cc:21:1: error: extended character   is not valid in an identifier
a.cc:21:1: error: extended character   is not valid in an identifier
a.cc:21:1: error: extended character   is not valid in an identifier
a.cc:21:1: error: extended character   is not valid in an identifier
a.cc:21:1: error: extended character   is not valid in an identifier
a.cc:22:1: error: extended character   is not valid in an identifier
   22 |     }
      | ^
a.cc:22:1: error: extended character   is not valid in an identifier
a.cc:22:1: error: extended character   is not valid in an identifier
a.cc:26:1: error: extended character   is not valid in an identifier
   26 |     ll N,A,B,K;
      | ^
a.cc:26:1: error: extended character   is not valid in an identifier
a.cc:26:1: error: extended character   is not valid in an identifier
a.cc:27:1: error: extended character   is not valid in an identifier
   27 |     cin>>N>>A>>B>>K;
      | ^
a.cc:27:1: error: extended character   is not valid in an identifier
a.cc:27:1: error: extended character   is not valid in an identifier
a.cc:28:1: error: extended character   is not valid in an identifier
   28 |     init();
      | ^
a.cc:28:1: error: extended character   is not valid in an identifier
a.cc:28:1: error: extended character   is not valid in an identifier
a.cc:29:1: error: extended character   is not valid in an identifier
   29 |     ll i;long long j,sum,ans=0;
      | ^
a.cc:29:1: error: extended character   is not valid in an identifier
a.cc:29:1: error: extended character   is not valid in an identifier
a.cc:30:1: error: extended character   is not valid in an identifier
   30 |     for(i=0;i<=N;i++){
      | ^
a.cc:30:1: error: extended character   is not valid in an identifier
a.cc:30:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
   31 |         sum=i*A;
      | ^
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
   32 |             if((K-sum)>=0&&(K-sum)%B==0){
      | ^
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
   33 |                 j=(K-sum)/B;
      | ^
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
   34 |                 if(j>N) continue;
      | ^
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
   35 |                 ans=ans+C(N,i)*C(N,j);
      | ^
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
   36 |                 ans%=M;
      | ^
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:37:1: error: extended character   is not valid in an identifier
   37 |             }
      | ^
a.cc:37:1: error: extended character   is not valid in an identifier
a.cc:37:1: error: extended character   is not valid in an identifier
a.cc:37:1: error: extended character   is not valid in an identifier
a.cc:37:1: error: extended character   is not valid in an identifier
a.cc:37:1: error: extended character   is not valid in an identifier
a.cc:37:1: error: extended characte