#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl; #define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl; template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } using namespace std; typedef long long ll; template vector> vec2d(int n, int m, T v){ return vector>(n, vector(m, v)); } template vector>> vec3d(int n, int m, int k, T v){ return vector>>(n, vector>(m, vector(k, v))); } template void print_vector(vector v, char delimiter=' '){ if(v.empty()) { cout << endl; return; } for(int i = 0; i+1 < v.size(); i++) cout << v[i] << delimiter; cout << v.back() << endl; } using P = pair; using mint = atcoder::modint998244353; struct node{ mint sum, prod; }; node e() { return node{mint(0), mint(1)}; } node opl(node n1, node n2){ // 左から return node{n1.sum+n2.sum*n1.prod, n1.prod*n2.prod}; } node opr(node n1, node n2){ // 右から return node{n2.sum+n1.sum*n2.prod, n1.prod*n2.prod}; } int main(){ ios::sync_with_stdio(false); cin.tie(0); cout << setprecision(10) << fixed; int n; cin >> n; vector a(n); vector

p(n); for(int i = 0; i < n; i++) { cin >> a[i]; p[i] = P(a[i], i); } sort(p.begin(), p.end()); atcoder::segtree sgtl(vector(n, node{mint(1), mint(1)})); atcoder::segtree sgtr(vector(n, node{mint(1), mint(1)})); mint ans = 0; for(auto [x, i]: p){ auto qr = sgtr.prod(0, i); auto ql = sgtl.prod(i+1, n); // cout << qr.sum.val() << ' ' << qr.prod.val() << ' ' << ql.sum.val() << ' ' << ql.prod.val() << endl; ans += (ql.sum+1)*(qr.sum+1)*x; sgtl.set(i, node{mint(2), mint(2)}); sgtr.set(i, node{mint(2), mint(2)}); } cout << ans.val() << endl; }