#include #include // cout, endl, cin #include // string, to_string, stoi #include // vector #include // min, max, swap, sort, reverse, lower_bound, upper_bound #include // pair, make_pair #include // tuple, make_tuple #include // int64_t, int*_t #include // printf #include // map #include // queue, priority_queue #include // set #include // stack #include // deque #include // unordered_map #include // unordered_set #include // bitset #include // isupper, islower, isdigit, toupper, tolower #include #include #include #include #include using namespace std; using namespace atcoder; #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define repi(i, a, b) for (int i = (int)(a); i < (int)(b); i++) #define rep2(i, m, n) for (int i = (m); i < (n); ++i) #define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i) #define drep(i, n) drep2(i, n, 0) //#define endl '\n' #define all(x) (x).begin(),(x).end() #define arr(x) (x).rbegin(),(x).rend() typedef long long ll; typedef unsigned long long ull; const ll inf=1e18; //const int inf=1e7; using graph = vector > ; using P= pair; using vi=vector; using vvi=vector; using vll=vector; using vvll=vector; using vp=vector

; using vvp=vector; using vd=vector; using vvd =vector; //string T="ABCDEFGHIJKLMNOPQRSTUVWXYZ"; //string S="abcdefghijklmnopqrstuvwxyz"; //g++ main.cpp -std=c++17 -I . //cout < bool chmin(T& a, T b) { if (a > b) { a = b; return true; } else return false; } template bool chmax(T& a, T b) { if (a < b) { a = b; return true; } else return false; } struct edge{ int to; ll cost;int dir; edge(int to,ll cost,int dir) : to(to),cost(cost),dir(dir){} }; using ve=vector; using vve=vector; using mint = modint998244353; using vm=vector; using vvm=vector; const int mod = 998244353; //int mod = 1e9+7; constexpr ll MAX = 2001000; ll fact[MAX],finv[MAX],inv[MAX]; void initcomb(){ fact[0]=fact[1]=1; finv[0]=finv[1]=1; inv[1]=1; for(int i=2;i par, siz; UnionFind(int n) : par(n, -1) , siz(n, 1) { } int root(int x) { if (par[x] == -1) return x; else return par[x] = root(par[x]); } bool issame(int x, int y) { return root(x) == root(y); } bool unite(int x, int y) { x = root(x), y = root(y); if (x == y) return false; //if (siz[x] < siz[y]) swap(x, y); par[y] = x; siz[x] += siz[y]; return true; } int size(int x) { return siz[root(x)]; } }; struct Compress{ vll a; map d,d2; int cnt; Compress() :cnt(0) {} void add(ll x){a.push_back(x);} void init(){ sets(a.begin(),a.end()); for(auto y:s)d[y]=cnt++; for(auto&y:a)y=d[y]; for(auto u:d)d2[u.second]=u.first; } ll to(ll x){return d[x];} //変換先 ll from(ll x){return d2[x];}//逆引き int size(){return cnt;} }; vll anss; void solve(int test){ int n,m; cin >> n >> m; vi a(n);rep(i,n)cin >> a[i]; vi cnt(n+1); rep(i,n)cnt[a[i]]++; vi sum(n+1); sum[0]=cnt[0]; repi(i,1,n+1)sum[i]=sum[i-1]+cnt[i]; vll dp(1,1); vvll nums(n); int last=-1; int tot=0; for(int i=n-1; i>=0; i--)if(cnt[i]){ nums[i].resize(3); int l=-1,r=-1; if(last==-1){ l=0,r=0; } else { r=last; if(i>=0)r-=sum[i]; l=tot-r; } { int nr=r; if(i-1>=0)nr+=sum[i-1]; if(nr==i)nums[i][1]+=1; nums[i][1]%=mod; } { int nl=l; if(i-1>=0)nl+=sum[i-1]; if(nl==i)nums[i][1]+=1; nums[i][1]%=mod; } { int sa=0; if(i-1>=0)sa+=sum[i-1]; int x=i-l-sa; int y=i-r-sa; if(x>0 && y>0 && x+y==cnt[i]){ nums[i][2]+=comb(cnt[i],x); nums[i][2]%=mod; } } if(cnt[i])last=i; tot+=cnt[i]; } if(nums[last][1]==2)nums[last][1]=1; deque

dq; rep(i,n)if(cnt[i])dq.push_back(P(3,i)); while(dq.size()>=2){ int v=dq.front().second;dq.pop_front(); int u=dq.front().second;dq.pop_front(); nums[v]=convolution(nums[u],nums[v]); dq.push_back(P(nums[v].size(),v)); } dp=nums[dq.front().second]; mint ans=0; rep(i,dp.size())ans+=mint(1)*comb(m,i)*dp[i]; anss.push_back(ans.val()); } //g++ main.cpp -std=c++17 -I . int main(){cin.tie(0);ios::sync_with_stdio(false); int t=1;cin >>t; initcomb(); rep(test,t)solve(test); for(auto ans:anss)cout << ans << endl; }