#include<bits/stdc++.h>
#define pb push_back
#define P make_pair
#define fi first
#define se second
#define bit(s,x) (((s)>>(x))&1)
#define pnp(s) __builtin_popcountll(s)
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define per(i,a,b) for(int i=(a);i>=(b);--i)
using namespace std;
typedef long long ll; 
typedef unsigned long long ull;
typedef pair<int,int> pii;
inline ll read(){
	ll x=0,f=1,c=getchar();
	while(c<'0'||c>'9')f=(c=='-'?-1:1),c=getchar();
	while(c>='0'&&c<='9')x=(x<<1)+(x<<3)+(c^48),c=getchar();
	return x*f;
}
const int mod=998244353;
inline int fp(int x,ll p=mod-2,int m=mod,int res=1){
	for(;p;p>>=1){if(p&1)res=1ll*res*x%m;x=1ll*x*x%m;}
	return res;
}
inline void Ad(int &x,int y){x=x+y>=mod?x+y-mod:x+y;}
inline void Mi(int &x,int y){x=x-y<0?x-y+mod:x-y;}
const int N=5e5+3;
int n,C,a[N],rt[N],q[N],fac[N],p[N];
const int M=1e7;
int t[M],son[M][2],tt;
inline void ad(int &x,int l,int r,int nx){
	int p=++tt;
	t[p]=t[x]+1,son[p][0]=son[x][0],son[p][1]=son[x][1];
	x=p;
	if(l==r)return ;int mid=(l+r)>>1;
	if(nx<=mid)ad(son[x][0],l,mid,nx);
	else ad(son[x][1],mid+1,r,nx);
}
inline int qr(int x,int y,int l,int r,int k){
	if(l==r)return q[l];int mid=(l+r)>>1;
	if(t[son[x][0]]-t[son[y][0]]>=k)return qr(son[x][0],son[y][0],l,mid,k);
	return qr(son[x][1],son[y][1],mid+1,r,k-t[son[x][0]]-t[son[y][0]]);
}
inline int solve(int l,int r,int a,int b){
	if(r-l+1<=C)return 1;
	int x=qr(rt[r],rt[l-1],1,n,a+b-1),lp=l+(a-1)*C,rp=r-(b-1)*C;
	if(x>lp&&x<rp)return 1ll*solve(l,x,a,1)*solve(x,r,1,b)%mod;
	if(lp+C>=rp){
		if(x<=lp)++a;
		else ++b;
		return 1ll*p[a-1]*p[b-1]%mod*fac[r-l+1-a-b+2]%mod;
	}
	if(x<=lp)return solve(l,r,a+1,b);
	if(x>=rp)return solve(l,r,a,b+1);
}
inline void solve(){
	n=read(),C=read();tt=0;
	int cnt=1; p[0]=1;
	rep(i,1,n){
		p[i]=1ll*p[i-1]*cnt%mod;
		Ad(cnt,C-1);
	}
	rep(i,1,n)ad(rt[i]=rt[i-1],1,n,a[i]=read()),q[a[i]]=i;
	printf("%d\n",solve(1,n,1,1));
}
int main() {
    //freopen("data.in", "r", stdin);
    // freopen("myans.out","w",stdout);
	fac[0]=1;rep(i,1,N-1)fac[i]=1ll*fac[i-1]*i%mod;
	int T=read();while(T--)solve();
    return 0;
}