結果

問題 No.2337 Equidistant
ユーザー ecottea
提出日時 2023-06-02 23:13:54
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 1,287 ms / 4,000 ms
コード長 17,183 bytes
コンパイル時間 4,413 ms
コンパイル使用メモリ 276,008 KB
最終ジャッジ日時 2025-02-13 20:22:24
ジャッジサーバーID
(参考情報)
judge1 / judge4
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ファイルパターン 結果
sample AC * 1
other AC * 28
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ソースコード

diff #
プレゼンテーションモードにする

#ifndef HIDDEN_IN_VS //
//
#define _CRT_SECURE_NO_WARNINGS
//
#include <bits/stdc++.h>
using namespace std;
//
using ll = long long; // -2^63 2^63 = 9 * 10^18int -2^31 2^31 = 2 * 10^9
using pii = pair<int, int>; using pll = pair<ll, ll>; using pil = pair<int, ll>; using pli = pair<ll, int>;
using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>;
using vl = vector<ll>; using vvl = vector<vl>; using vvvl = vector<vvl>;
using vb = vector<bool>; using vvb = vector<vb>; using vvvb = vector<vvb>;
using vc = vector<char>; using vvc = vector<vc>; using vvvc = vector<vvc>;
using vd = vector<double>; using vvd = vector<vd>; using vvvd = vector<vvd>;
template <class T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
using Graph = vvi;
//
const double PI = acos(-1);
const vi DX = { 1, 0, -1, 0 }; // 4
const vi DY = { 0, 1, 0, -1 };
int INF = 1001001001; ll INFL = 4004004004004004004LL;
double EPS = 1e-15;
//
struct fast_io { fast_io() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(18); } } fastIOtmp;
//
#define all(a) (a).begin(), (a).end()
#define sz(x) ((int)(x).size())
#define lbpos(a, x) (int)distance((a).begin(), std::lower_bound(all(a), x))
#define ubpos(a, x) (int)distance((a).begin(), std::upper_bound(all(a), x))
#define Yes(b) {cout << ((b) ? "Yes\n" : "No\n");}
#define YES(b) {cout << ((b) ? "YES\n" : "NO\n");}
#define rep(i, n) for(int i = 0, i##_len = int(n); i < i##_len; ++i) // 0 n-1
#define repi(i, s, t) for(int i = int(s), i##_end = int(t); i <= i##_end; ++i) // s t
#define repir(i, s, t) for(int i = int(s), i##_end = int(t); i >= i##_end; --i) // s t
#define repe(v, a) for(const auto& v : (a)) // a
#define repea(v, a) for(auto& v : (a)) // a
#define repb(set, d) for(int set = 0; set < (1 << int(d)); ++set) // d
#define repp(a) sort(all(a)); for(bool a##_perm = true; a##_perm; a##_perm = next_permutation(all(a))) // a
#define smod(n, m) ((((n) % (m)) + (m)) % (m)) // mod
#define uniq(a) {sort(all(a)); (a).erase(unique(all(a)), (a).end());} //
#define EXIT(a) {cout << (a) << endl; exit(0);} //
//
template <class T> inline ll pow(T n, int k) { ll v = 1; rep(i, k) v *= n; return v; }
template <class T> inline bool chmax(T& M, const T& x) { if (M < x) { M = x; return true; } return false; } // true
    
template <class T> inline bool chmin(T& m, const T& x) { if (m > x) { m = x; return true; } return false; } // true
    
template <class T> inline T get(T set, int i) { return (set >> i) & T(1); }
//
template <class T, class U> inline istream& operator>>(istream& is, pair<T, U>& p) { is >> p.first >> p.second; return is; }
template <class T> inline istream& operator>>(istream& is, vector<T>& v) { repea(x, v) is >> x; return is; }
template <class T> inline vector<T>& operator--(vector<T>& v) { repea(x, v) --x; return v; }
template <class T> inline vector<T>& operator++(vector<T>& v) { repea(x, v) ++x; return v; }
#endif //
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#ifdef _MSC_VER
#include "localACL.hpp"
#endif
//using mint = modint1000000007;
using mint = modint998244353;
//using mint = modint; // mint::set_mod(m);
namespace atcoder {
inline istream& operator>>(istream& is, mint& x) { ll x_; is >> x_; x = x_; return is; }
inline ostream& operator<<(ostream& os, const mint& x) { os << x.val(); return os; }
}
using vm = vector<mint>; using vvm = vector<vm>; using vvvm = vector<vvm>;
#endif
#ifdef _MSC_VER // Visual Studio
#include "local.hpp"
#else // gcc
inline int popcount(int n) { return __builtin_popcount(n); }
inline int popcount(ll n) { return __builtin_popcountll(n); }
inline int lsb(int n) { return n != 0 ? __builtin_ctz(n) : -1; }
inline int lsb(ll n) { return n != 0 ? __builtin_ctzll(n) : -1; }
inline int msb(int n) { return n != 0 ? (31 - __builtin_clz(n)) : -1; }
inline int msb(ll n) { return n != 0 ? (63 - __builtin_clzll(n)) : -1; }
#define gcd __gcd
#define dump(...)
#define dumpel(v)
#define dump_list(v)
#define dump_mat(v)
#define input_from_file(f)
#define output_to_file(f)
#define Assert(b) { if (!(b)) while (1) cout << "OLE"; }
#endif
//O(n + m)
/*
* (, ) n m
*
* n :
* m : n-1
* undirected : true
* one_indexed : 1-indexed true
*/
Graph read_Graph(int n, int m = -1, bool undirected = true, bool one_indexed = true) {
// verify : https://codeforces.com/contest/764/problem/C
Graph g(n);
if (m == -1) m = n - 1;
rep(i, m) {
int a, b;
cin >> a >> b;
if (one_indexed) { --a; --b; }
g[a].push_back(b);
if (undirected) g[b].push_back(a);
}
return g;
}
//
/*
* Rooted_tree() : O(1)
*
*
* Rooted_tree(Graph g, int r) : O(n)
* g r
*/
struct Rooted_tree {
// verify : https://onlinejudge.u-aizu.ac.jp/courses/lesson/1/ALDS1/all/ALDS1_7_A
struct Node {
int parent = -1; // -1
vi child; //
int depth = -1; //
int& dist = depth; // 1
int weight = -1; //
int height = -1; //
#ifdef _MSC_VER
friend ostream& operator<<(ostream& os, const Node& v) {
os << "(p:" << v.parent << ", c:[";
repe(s, v.child) os << s << " ";
os << "], d:" << v.depth << ", w:" << v.weight << ", h:" << v.height << ")";
return os;
}
#endif
};
int n; //
int r; //
vector<Node> v; //
//
Rooted_tree() : n(0), r(-1) {}
Rooted_tree(const Graph& g, int r_) : n(sz(g)), r(r_), v(n) {
// s : p : s
function<void(int, int)> dfs = [&](int s, int p) {
v[s].parent = p;
v[s].child.clear();
v[s].weight = 0;
v[s].height = 0;
repe(t, g[s]) {
if (t == p) continue;
v[t].depth = v[s].depth + 1;
dfs(t, s);
v[s].child.push_back(t);
v[s].weight += v[t].weight + 1;
chmax(v[s].height, v[t].height + 1);
}
};
// r
v[r].depth = 0;
dfs(r, -1);
}
//
Node const& operator[](int i) const { return v[i]; }
Node& operator[](int i) { return v[i]; }
//
int size() const { return n; }
#ifdef _MSC_VER
friend ostream& operator<<(ostream& os, const Rooted_tree& rt) {
rep(i, rt.n) os << rt[i] << endl;
return os;
}
#endif
};
//O(n)
/*
* n rt
*
* in[s] : DFS s 0
* out[s] : DFS s 2n-1
* pos[t] : DFS t 2n-1
*/
template <class TREE>
void euler_tour(const TREE& rt, vi& in, vi& out, vi& pos) {
// verify : https://onlinejudge.u-aizu.ac.jp/courses/library/5/GRL/all/GRL_5_C
int n = sz(rt);
int time = 0;
in.resize(n);
out.resize(n);
pos.resize(2 * n - 1);
//
function<void(int)> rf = [&](int s) {
// s
in[s] = time;
pos[time++] = s;
repe(t, rt[s].child) {
rf(t);
pos[time++] = s;
}
// s
out[s] = time;
};
//
rf(rt.r);
}
//
/*
*
*
* Lowest_common_ancestor<TREE>(rt) : O(n)
* rt
*
* int lca(int s, int t) : O(log n)
* s, t
*
* ll dist(int s, int t) : O(log n)
* s, t
*
* int jump(int s, int t, int i) : O(log n)
* s t i 0-indexed -1
*
*
*/
pli op_LCA(pli a, pli b) { return min(a, b); }
pli e_LCA() { return { INFL, -1 }; }
template <class TREE>
struct Lowest_common_ancestor {
TREE rt;
//
// in[v] : v
// out[v] : v
// pos[t] : t
vi in, out, pos;
//
// seg[t] : t (, )
using SEG = segtree<pli, op_LCA, e_LCA>;
SEG seg;
// O(n)
Lowest_common_ancestor(const TREE& rt_) : rt(rt_) {
// verify : https://onlinejudge.u-aizu.ac.jp/courses/library/5/GRL/all/GRL_5_C
//
euler_tour(rt, in, out, pos);
//
//
int n = sz(rt.v);
vector<pli> depth(2 * n - 1);
rep(t, 2 * n - 1) depth[t] = { rt[pos[t]].depth, pos[t] };
seg = SEG(depth);
}
Lowest_common_ancestor() {}
// s, t
int lca(int s, int t) {
// verify : https://onlinejudge.u-aizu.ac.jp/courses/library/5/GRL/all/GRL_5_C
// s t
int left = min(in[s], in[t]);
// s t
int right = max(out[s], out[t]);
//
return seg.prod(left, right).second;
}
// s, t
ll dist(int s, int t) {
int r = lca(s, t);
//
return rt[s].dist + rt[t].dist - 2 * rt[r].dist;
}
// s t i 0-indexed -1
int jump(int s, int t, int i) {
// verify : https://judge.yosupo.jp/problem/jump_on_tree
int r = lca(s, t);
int ds = rt[s].depth, dt = rt[t].depth, dr = rt[r].depth;
int dist = ds + dt - 2 * dr;
int res;
if (i > dist) res = -1;
else if (i <= ds - dr) {
int j = seg.max_right(out[s] - 1, [&](pli tmp) { return tmp.first > ds - i; });
res = pos[j];
}
else {
int j = seg.min_left(in[t] + 1, [&](pli tmp) { return tmp.first >= dt - (dist - i); });
res = pos[j];
}
return res;
}
};
// DPO(n)
/*
* g s∈[0..n)
* g s
* s∈[0..n) s tj
* s-t t sub[s][j]
*
* T merge(T x, T y, int s) :
* s 2 x, y
* s
*
* T e(int s) :
* s merge()
*
* T leaf(int s) :
* s s
*
* T apply(T x, int p, int s) :
* s x
* p→s p
*/
template <class T, T(*merge)(T, T, int), T(*e)(int), T(*leaf)(int), T(*apply)(T, int, int)>
vector<T> rerooting(const Graph& g, vector<vector<T>>* sub = nullptr) {
// verify : https://atcoder.jp/contests/abc149/tasks/abc149_f
int n = sz(g);
vector<T> res(n);
// sub[s][i] : s i t
// s-t t
if (sub == nullptr) sub = new vector<vector<T>>;
sub->resize(n);
rep(s, n) {
(*sub)[s] = vector<T>(sz(g[s]));
rep(i, sz(g[s])) (*sub)[s][i] = e(g[s][i]);
}
// p-s s
// p : 0 s
// si : s p
function<void(int, int, int)> dfs1 = [&](int s, int p, int si) {
// is_leef : s
bool is_leef = true;
rep(ti, sz(g[s])) {
int t = g[s][ti];
if (t == p) continue;
is_leef = false;
// s-t t
dfs1(t, s, ti);
// s→t
//
if (p != -1) (*sub)[p][si] = merge((*sub)[p][si], apply((*sub)[s][ti], s, t), s);
}
// s
if (is_leef && p != -1) (*sub)[p][si] = leaf(s);
};
dfs1(0, -1, -1);
// s
// p : 0 s
// val : s-p p
function<void(int, int, const T&)> dfs2 = [&](int s, int p, const T& val) {
// ds : s s
vector<T> ds{ p != -1 ? apply(val, s, p) : e(s) };
rep(ti, sz(g[s])) {
int t = g[s][ti];
if (t == p) {
(*sub)[s][ti] = val;
continue;
}
// s-t t
// s→t s
ds.push_back(apply((*sub)[s][ti], s, t));
}
int k = sz(ds);
// acc_l[acc_r] : s [] s
vector<T> acc_l(k + 1, e(s)), acc_r(k + 1, e(s));
rep(i, k) acc_l[i + 1] = merge(acc_l[i], ds[i], s);
repir(i, k - 1, 0) acc_r[i] = merge(acc_r[i + 1], ds[i], s);
// s s
res[s] = acc_l[k];
int i = 1;
rep(ti, sz(g[s])) {
int t = g[s][ti];
if (t == p) continue;
// s s→t
// t-s s
dfs2(t, s, merge(acc_l[i], acc_r[i + 1], s));
i++;
}
};
dfs2(0, -1, e(0)); // 1
return res;
/*
using T = int;
T merge(T x, T y, int s) { return max(x, y); }
T e(int s) { return 0; }
T leaf(int s) { return 0; }
T apply(T x, int p, int s) { return x + 1; }
vector<T> solve_by_rerooting(const Graph& g, vector<vector<T>>* sub = nullptr) {
return rerooting<T, merge, e, leaf, apply>(g, sub);
}
*/
};
//O(n)
/*
* g s∈[0..n) s t
* s-t t
*
* DP
*/
using T_ss = int;
T_ss merge_ss(T_ss x, T_ss y, int s) { return x + y - 1; }
T_ss e_ss(int s) { return 1; }
T_ss leaf_ss(int s) { return 1; }
T_ss apply_ss(T_ss x, int p, int s) { return x + 1; }
vvi subtree_size(Graph& g) {
// verify : https://atcoder.jp/contests/abc149/tasks/abc149_f
vvi res;
rerooting<T_ss, merge_ss, e_ss, leaf_ss, apply_ss>(g, &res);
return res;
}
int main() {
// input_from_file("input.txt");
// output_to_file("output.txt");
int n, q;
cin >> n >> q;
auto g = read_Graph(n);
auto ws = subtree_size(g);
Rooted_tree rt(g, 0);
Lowest_common_ancestor<Rooted_tree> LCA(rt);
vector<unordered_map<int, int>> id(n);
rep(s, n) rep(i, sz(g[s])) id[s][g[s][i]] = i;
rep(hoge, q) {
int s, t;
cin >> s >> t;
s--; t--;
auto d = LCA.dist(s, t);
if (d % 2 == 1) {
cout << 0 << endl;
continue;
}
int m = LCA.jump(s, t, d / 2);
int ms = LCA.jump(s, t, d / 2 - 1);
int mt = LCA.jump(s, t, d / 2 + 1);
int res = n - ws[m][id[m][ms]] - ws[m][id[m][mt]];
cout << res << endl;
}
}
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