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| #include <bits/stdc++.h>
using namespace std;
const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;
#define int long long
#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))
#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
using ll=long long;
const int mod=998244353,g=3,gi=332748118,N=1e5+9;
int tt,n,x,k,fac[N],inv[N],a[N],dp[N];
int rev[N],a0[N],a1[N],bit,lim;
int powmod(int a,int b){
int res=1;
for(;b>0;b>>=1,a=1ll*a*a%mod)if(b&1)res=1ll*res*a%mod;
return res;
}
void init(int n){
fac[0]=1,inv[0]=1;
for(int i=1;i<=n;++i)fac[i]=1ll*fac[i-1]*i%mod;
inv[n]=powmod(fac[n],mod-2);
for(int i=n-1;i;--i)inv[i]=1ll*inv[i+1]*(i+1)%mod;
}
void NTT(int *aa,int type){
for(int i=0;i<lim;++i)if(i<rev[i])swap(aa[i],aa[rev[i]]);
for (int k = 1; k < lim; k <<= 1){
int wn = powmod((type == 1 ? g : gi), (mod - 1) / (k << 1));
for (int i = 0; i < lim; i += (k << 1)){
int w=1;
for(int j=0;j<k;++j,w=1ll*w*wn%mod){
ll x=aa[i+j],y=1ll*w * aa[i + j + k]%mod;
aa[i + j] = (x + y)%mod;
aa[i + j + k] = ((x - y)%mod+mod)%mod;
}
}
}
if (type == 1)
return;
int invn = powmod(lim,mod-2);
for (int i = 0; i < lim; ++i)
aa[i] = 1ll*aa[i] * invn%mod;
}
void solve(){
cin>>n>>k>>x;
for(int i=0;i<=k;++i)dp[i]=0;
lim=1,bit=0;
while(lim<=2*k)lim<<=1,bit+=1;
for (int i = 0; i < lim; ++i)
rev[i] = (rev[i >> 1] >> 1) | ((i & 1) << (bit - 1));
for(int i=1,m;i<=n;++i){
m=1;
cin>>a[i];
for(int j=0;j<=k;++j){
a0[j]=1ll*dp[j]*inv[j]%mod;
a1[j]=1ll*m*inv[j]%mod;
m=1ll*m*a[i]%mod;
}
for(int j=k+1;j<=lim;++j)a0[j]=a1[j]=0;
NTT(a0,1),NTT(a1,1);
for(int i=0;i<lim;++i)a0[i]=1ll*a0[i]*a1[i]%mod;
NTT(a0,0);
m=1;
for(int j=0;j<=k;++j){
dp[j]=(1ll*dp[j]+1ll*m*x%mod+1ll*a0[j]*x%mod*fac[j]%mod)%mod;
m=1ll*m*a[i]%mod;
}
}
cout<<dp[k]<<"\n";
}
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0);
init(1e4+100);
cin>>tt;
f(sb,1,tt)solve();
return 0;
}
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