#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using ll = long long; using pii = pair; using pll = pair; template using vc = vector; template using vvc = vector>; template using vvvc = vector>>; template using pq = priority_queue,greater>; template inline bool chmax(T &a, const S &b) { return (a < b ? a = b, 1 : 0); } template inline bool chmin(T &a, const S &b) { return (a > b ? a = b, 1 : 0); } int dx4[] = {1,0,-1,0}; int dy4[] = {0,1,0,-1}; #define overload5(a, b, c, d, e, name, ...) name #define overload4(a, b, c, d, name, ...) name #define REP0(n) for(ll jidlsjf = 0; jidlsjf < n; ++jidlsjf) #define REP1(i, n) for(ll i = 0; i < (n); ++i) #define REP2(i, a, b) for(ll i = (a); i < (b); ++i) #define REP3(i, a, b, c) for(ll i = (a); i < (b); i += (c)) #define rep(...) overload4(__VA_ARGS__, REP3, REP2, REP1, REP0)(__VA_ARGS__) #define per0(n) for(int jidlsjf = 0; jidlsjf < (n); ++jidlsjf) #define per1(i, n) for(ll i = (n)-1; i >= 0; --i) #define per2(i, a, b) for(ll i = (a)-1; i >= b; --i) #define per3(i, a, b, c) for(ll i = (a)-1; i >= (b); i -= (c)) #define per(...) overload4(__VA_ARGS__, per3, per2, per1, per0)(__VA_ARGS__) #define fi first #define se second #define pb push_back #define ppb pop_back #define ppf pop_front #define drop(s) cout << #s << endl, exit(0) #define si(c) (int)(c).size() #define lb(c, x) distance((c).begin(), lower_bound(all(c), (x))) #define lbg(c, x) distance((c).begin(), lower_bound(all(c), (x), greater{})) #define ub(c, x) distance((c).begin(), upper_bound(all(c), (x))) #define ubg(c, x) distance((c).begin(), upper_bound(all(c), (x), greater{})) #define rng(v, l, r) v.begin() + (l), v.begin() + (r) #define all(c) c.begin(), c.end() #define rall(c) c.rbegin(), c.rend() #define SORT(v) sort(all(v)) #define REV(v) reverse(all(v)) #define UNIQUE(x) SORT(x), x.erase(unique(all(x)), x.end()) #define MIN(v) *min_element(all(v)) #define MAX(v) *max_element(all(v)) #define overload2(_1, _2, name, ...) name #define vec(type, name, ...) vector name(__VA_ARGS__) #define vv(type, name, h, ...) vector> name(h, vector(__VA_ARGS__)) #define vvv(type, name, h, w, ...) vector>> name(h, vector>(w, vector(__VA_ARGS__))) constexpr int mod = 998244353; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n; cin >> n; vca(n),id; rep(i,n) { cin >> a[i]; if(a[i] == n) id.pb(i); } if(id.empty()) { cout << 0 << "\n"; return 0; } vcmi(n,n),cnt(n+1),cnt2(n+1); vc>mp(n); rep(i,n) { cnt2[a[i]]++; for(int j:id) { chmin(mi[i],a[(i+j)%n]); } cnt[mi[i]]++; for(int j:id) { int nxt = (i+n-j)%n; mp[nxt][a[i]]++; } } int sum = 0; int ans = n; per(i,n+1,1) { sum += cnt[i]; if(i == n) { sum--; continue; } if(cnt2[i]) { int tmp = 0; rep(j,n) { if(mp[j].count(i) && mp[j][i] == cnt2[i] && mi[j] == i) { tmp++; } } ans = 1ll*ans*tmp%mod; sum--; } else { ans = 1ll*ans*sum%mod; sum--; } } cout << ans << "\n"; }