/* このコード、と~おれ! Be accepted! ∧_∧  (。・ω・。)つ━☆・*。 ⊂   ノ    ・゜+.  しーJ   °。+ *´¨)          .· ´¸.·*´¨) ¸.·*¨)           (¸.·´ (¸.·'* ☆ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include ////多倍長整数, cpp_intで宣言 //#include //using namespace boost::multiprecision; //#pragma gcc target ("avx2") //#pragma gcc optimization ("Ofast") //#pragma gcc optimization ("unroll-loops") #define rep(i, n) for(int i = 0; i < (n); ++i) #define printynl(a) printf(a ? "yes\n" : "no\n") #define printyn(a) printf(a ? "Yes\n" : "No\n") #define printYN(a) printf(a ? "YES\n" : "NO\n") #define printim(a) printf(a ? "possible\n" : "imposible\n") #define printdb(a) printf("%.50lf\n", a) //少数出力 #define printLdb(a) printf("%.50Lf\n", a) //少数出力 #define printdbd(a) printf("%.16lf\n", a) //少数出力(桁少なめ) #define prints(s) printf("%s\n", s.c_str()) //string出力 #define all(x) (x).begin(), (x).end() #define deg_to_rad(deg) (((deg)/360.0L)*2.0L*PI) #define rad_to_deg(rad) (((rad)/2.0L/PI)*360.0L) #define Please return #define AC 0 #define manhattan_dist(a, b, c, d) (abs(a - c) + abs(b - d)) /*(a, b) から (c, d) のマンハッタン距離 */ #define inf numeric_limits::infinity(); #define linf numeric_limits::infinity() using ll = long long; using ull = unsigned long long; constexpr int INF = 1073741823; constexpr int MINF = -1073741823; constexpr ll LINF = ll(4661686018427387903); constexpr ll MOD = 1e9 + 7; constexpr long double eps = 1e-6; const long double PI = acosl(-1.0L); using namespace std; void scans(string& str) { char c; str = ""; scanf("%c", &c); if (c == '\n')scanf("%c", &c); while (c != '\n' && c != -1 && c != ' ') { str += c; scanf("%c", &c); } } void scanc(char& str) { char c; scanf("%c", &c); if (c == -1)return; while (c == '\n') { scanf("%c", &c); } str = c; } double acot(double x) { return PI / 2 - atan(x); } ll LSB(ll n) { return (n & (-n)); } template T chmin(T& a, const T& b) { if (a > b)a = b; return a; } template T chmax(T& a, const T& b) { if (a < b)a = b; return a; } /*-----------------------------------------ここからコード-----------------------------------------*/ /* * @title template(graph) * @docs kyopro/docs/graph_template.md */ template struct edge { T cost; int from, to; edge(int from, int to) : from(from), to(to), cost(T(1)) {} edge(int from, int to, T cost) : from(from), to(to), cost(cost) {} }; template struct graph { int n; bool directed, weighted; vector>> g; graph(int n, bool directed, bool weighted) : g(n), n(n), directed(directed), weighted(weighted) {} void add_edge(int from, int to, T cost = T(1)) { g[from].emplace_back(from, to, cost); if (not directed) { g[to].emplace_back(to, from, cost); } } vector>& operator[](const int& idx) { return g[idx]; } void read(int e, bool one_indexed) { int a, b, c = 1; while (e--) { scanf("%d%d", &a, &b); if (weighted) { scanf("%d", &c); } if (one_indexed)--a, --b; add_edge(a, b, c); } } void read(int e, bool one_indexed, const string& format) { int a, b; T c = T(1); while (e--) { scanf("%d%d", &a, &b); if (weighted) { scanf(format, &c); } if (one_indexed)--a, --b; add_edge(a, b, c); } } }; /* * @title sparse-table * @docs kyopro/docs/sparsetable.md */ //RMQ template struct sparsetable { vector> table; vector logtable; vector a; int n; // 渡す配列, サイズ sparsetable(const vector a, int siz) : n(siz), a(a) { logtable.assign(n + 1, 0); for (int i = 2; i <= n; ++i)logtable[i] = logtable[i >> 1] + 1; table.assign(n, vector(logtable[n] + 1, 0)); } //リストバージョン sparsetable(initializer_list init) { a = init[0]; n = init[1]; logtable.assign(n + 1, 0); for (int i = 2; i <= n; ++i)logtable[i] = logtable[i >> 1] + 1; table.assign(n, vector(logtable[n] + 1, 0)); } //配列と大きさを渡して初期化 void init(const vector aa, int siz) { a = aa; n = siz; logtable.assign(n + 1, 0); for (int i = 2; i <= n; ++i)logtable[i] = logtable[i >> 1] + 1; table.assign(n, vector(logtable[n] + 1, 0)); } //構築 O(n log n) void build() { for (int k = 0; (1 << k) <= n; ++k) { for (int i = 0; i + (1 << k) <= n; ++i) { if (k) table[i][k] = (a[table[i][k - 1]] < a[table[i + (1 << (k - 1))][k - 1]] ? table[i][k - 1] : table[i + (1 << (k - 1))][k - 1]); else table[i][k] = i; } } } //[l, r) の RMQ O(1) int query(int l, int r) { int k = logtable[r - l]; return (a[table[l][k]] < a[table[r - (1 << k)][k]] ? table[l][k] : table[r - (1 << k)][k]); } }; /* * @title lowest-common-ancestor(weighted) * @docs kyopro/docs/LCA_weighted.md */ //重み付き template void eulertour(const int& now, const int& bef, int& cnt, graph& graph, const int& d, vector& vs, vector& depth, vector& id) { depth.emplace_back(d); vs.emplace_back(now); id[now] = min(id[now], cnt); for (const auto& aa : graph[now]) { if (aa.to != bef) { ++cnt; eulertour(aa.to, now, cnt, graph, d + aa.cost, vs, depth, id); ++cnt; depth.emplace_back(d); vs.emplace_back(now); } } } template struct LCA { vector vs, depth, id, tmp = { 0 }; graph tree; sparsetable table{ tmp, 0 }; int n, root; //木, 大きさ, 根 LCA(graph tree, int n, int root) : tree(tree), n(n), root(root) { id.assign(n, INF); int cnt = 0, d = 0; eulertour(root, -1, cnt, tree, d, vs, depth, id); table.init(depth, depth.size()); table.build(); } //LCA である頂点を返す int query(int l, int r) { if (id[l] > id[r])swap(l, r); return vs[table.query(id[l], id[r] + 1)]; } int depthq(int n) { return depth[id[n]]; } }; int main() { int n, q; scanf("%d", &n); graph tree(n, false, true); tree.read(n - 1, true); LCA lca(tree, n, 0); int v, p; scanf("%d", &q); rep(i, q) { scanf("%d%d", &p, &v); --p, --v; printf("%d\n", lca.depthq(p) + lca.depthq(v) - 2 * lca.depthq(lca.query(p, v))); } Please AC; }