#line 1 "Main.cpp" #include #include #include #include #include #include #line 4 "nachia\\graph\\graph.hpp" #include #line 5 "nachia\\array\\csr-array.hpp" namespace nachia{ template class CsrArray{ public: struct ListRange{ using iterator = typename std::vector::iterator; iterator begi, endi; iterator begin() const { return begi; } iterator end() const { return endi; } int size() const { return (int)std::distance(begi, endi); } Elem& operator[](int i) const { return begi[i]; } }; struct ConstListRange{ using iterator = typename std::vector::const_iterator; iterator begi, endi; iterator begin() const { return begi; } iterator end() const { return endi; } int size() const { return (int)std::distance(begi, endi); } const Elem& operator[](int i) const { return begi[i]; } }; private: int m_n; std::vector m_list; std::vector m_pos; public: CsrArray() : m_n(0), m_list(), m_pos() {} static CsrArray Construct(int n, std::vector> items){ CsrArray res; res.m_n = n; std::vector buf(n+1, 0); for(auto& [u,v] : items){ ++buf[u]; } for(int i=1; i<=n; i++) buf[i] += buf[i-1]; res.m_list.resize(buf[n]); for(int i=(int)items.size()-1; i>=0; i--){ res.m_list[--buf[items[i].first]] = std::move(items[i].second); } res.m_pos = std::move(buf); return res; } static CsrArray FromRaw(std::vector list, std::vector pos){ CsrArray res; res.m_n = pos.size() - 1; res.m_list = std::move(list); res.m_pos = std::move(pos); return res; } ListRange operator[](int u) { return ListRange{ m_list.begin() + m_pos[u], m_list.begin() + m_pos[u+1] }; } ConstListRange operator[](int u) const { return ConstListRange{ m_list.begin() + m_pos[u], m_list.begin() + m_pos[u+1] }; } int size() const { return m_n; } int fullSize() const { return (int)m_list.size(); } }; } // namespace nachia #line 6 "nachia\\graph\\graph.hpp" namespace nachia{ struct Graph { public: struct Edge{ int from, to; void reverse(){ std::swap(from, to); } }; using Base = std::vector>; Graph(int n = 0, bool undirected = false) : m_n(n), m_e(), m_isUndir(undirected) {} Graph(int n, const std::vector>& edges, bool undirected = false) : m_n(n), m_isUndir(undirected){ m_e.resize(edges.size()); for(std::size_t i=0; i& edges, bool undirected = false) : m_n(n), m_e(edges), m_isUndir(undirected) {} Graph(int n, std::vector&& edges, bool undirected = false) : m_n(n), m_e(edges), m_isUndir(undirected) {} int numVertices() const noexcept { return m_n; } int numEdges() const noexcept { return int(m_e.size()); } int addEdge(int from, int to){ m_e.push_back({ from, to }); return numEdges() - 1; } Edge& operator[](int ei) noexcept { return m_e[ei]; } const Edge& operator[](int ei) const noexcept { return m_e[ei]; } Edge& at(int ei) { return m_e.at(ei); } const Edge& at(int ei) const { return m_e.at(ei); } auto begin(){ return m_e.begin(); } auto end(){ return m_e.end(); } auto begin() const { return m_e.begin(); } auto end() const { return m_e.end(); } bool isUndirected() const noexcept { return m_isUndir; } void reverseEdges() noexcept { for(auto& e : m_e) e.reverse(); } void contract(int newV, const std::vector& mapping){ assert(numVertices() == int(mapping.size())); for(int i=0; i induce(int num, const std::vector& mapping) const { int n = numVertices(); assert(n == int(mapping.size())); for(int i=0; i indexV(n), newV(num); for(int i=0; i= 0) indexV[i] = ++newV[mapping[i]]; std::vector res; res.reserve(num); for(int i=0; i= 0) res[mapping[e.to]].addEdge(indexV[e.from], indexV[e.to]); return res; } CsrArray getEdgeIndexArray(bool undirected) const { std::vector> src; src.reserve(numEdges() * (undirected ? 2 : 1)); for(int i=0; i::Construct(numVertices(), src); } CsrArray getEdgeIndexArray() const { return getEdgeIndexArray(isUndirected()); } CsrArray getAdjacencyArray(bool undirected) const { std::vector> src; src.reserve(numEdges() * (undirected ? 2 : 1)); for(auto e : m_e){ src.emplace_back(e.from, e.to); if(undirected) src.emplace_back(e.to, e.from); } return CsrArray::Construct(numVertices(), src); } CsrArray getAdjacencyArray() const { return getAdjacencyArray(isUndirected()); } private: int m_n; std::vector m_e; bool m_isUndir; }; } // namespace nachia #line 8 "Main.cpp" using namespace std; using i32 = int32_t; using u32 = uint32_t; using i64 = int64_t; using u64 = uint64_t; #define rep(i,n) for(int i=0; i<(int)(n); i++) const i64 INF = 1001001001001001001; using Modint = atcoder::static_modint<998244353>; int main(){ int N; cin >> N; vector A(N); rep(i,N){ int a; cin >> a; A[i] = Modint::raw(a); } nachia::Graph G(N); rep(i,N-1){ int u,v; cin >> u >> v; G.addEdge(u-1, v-1); } auto adj = G.getAdjacencyArray(true); vector closed(N, 0); vector ord(N); rep(i,N) ord[i] = i; sort(ord.begin(), ord.end(), [&](int l, int r){ return A[l].val() > A[r].val(); }); Modint INV2 = Modint(2).inv(); vector bfs(N); vector par(N); vector dpE(N); vector dpX(N); Modint anssum = 0; Modint off = Modint(2).pow(N-1); for(int v : ord){ int p2=0; fill(par.begin(), par.end(), -1); fill(dpE.begin(), dpE.end(), Modint(1)); fill(dpX.begin(), dpX.end(), Modint(1)); bfs[p2++] = v; for(int w : bfs) for(int x : adj[w]) if(par[w] != x){ bfs[p2++] = x; par[x] = w; } for(int i=N-1; i>=1; i--){ int w = bfs[i], p = par[w]; if(closed[w]){ dpX[w] = 0; dpE[w] = 0; } Modint xw = 1 - (1 - dpX[w]) * INV2; dpE[p] = dpE[w] * INV2 * dpX[p] + dpE[p] * xw; dpX[p] *= xw; } Modint ans = dpE[v] * off; anssum += ans * A[v]; closed[v] = 1; } cout << anssum.val() << endl; return 0; } struct ios_do_not_sync{ ios_do_not_sync(){ std::ios::sync_with_stdio(false); std::cin.tie(nullptr); } } ios_do_not_sync_instance;