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test/yuki1326_block_cut_tree.test.cpp
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- Last update: 2026-03-22 13:47:31+09:00
- Problem: https://yukicoder.me/problems/no/1326
Depends on
- 二重連結成分分解(Biconnected Components)
(graph/biconnected_components.cpp)
- ブロックカット木(Block-Cut Tree)
(graph/block_cut_tree.cpp)
- HL分解(HL Decomposition)
(tree/hld.cpp)
- 高速入出力(Fast IO)
(util/fastio.cpp)
Code
#define PROBLEM "https://yukicoder.me/problems/no/1326"
#include <algorithm>
#include <vector>
#include <cstdio>
#include <cstring>
#include <string>
#include <type_traits>
#include "../util/fastio.cpp"
#include "../graph/block_cut_tree.cpp"
#include "../tree/hld.cpp"
int main() {
Scanner sc;
Printer pr;
int n, m;
sc.read(n, m);
BlockCutTree g(n);
for (int i = 0; i < m; ++i) {
int u, v;
sc.read(u, v);
--u, --v;
g.add_edge(u, v);
}
g.build();
HeavyLightDecomposition hld(g.tree);
hld.build();
vector<int> pref((int)g.tree.size());
for (int i = 0; i < (int)g.tree.size(); ++i) {
int v = hld.id_inv[i];
pref[v] = (g.rev[v] != -1);
if (hld.par[v] != -1) pref[v] += pref[hld.par[v]];
}
int q;
sc.read(q);
while (q--) {
int x, y;
sc.read(x, y);
--x, --y;
if (x == y) {
pr.println(0);
continue;
}
int u = g.id[x], v = g.id[y];
int a = hld.lca(u, v);
int ans = pref[u] + pref[v] - 2 * pref[a] + (g.rev[a] != -1);
if (g.is_articulation[x]) --ans;
if (g.is_articulation[y]) --ans;
pr.println(ans);
}
return 0;
}#line 1 "test/yuki1326_block_cut_tree.test.cpp"
#define PROBLEM "https://yukicoder.me/problems/no/1326"
#include <algorithm>
#include <vector>
#include <cstdio>
#include <cstring>
#include <string>
#include <type_traits>
#line 1 "util/fastio.cpp"
using namespace std;
extern "C" int fileno(FILE *);
extern "C" int isatty(int);
template<class T, class = void>
struct is_fastio_range : false_type {};
template<class T>
struct is_fastio_range<T, void_t<decltype(declval<T &>().begin()), decltype(declval<T &>().end())>> : true_type {};
template<class T, class = void>
struct has_fastio_value : false_type {};
template<class T>
struct has_fastio_value<T, void_t<decltype(declval<const T &>().value())>> : true_type {};
struct FastIoDigitTable {
char num[40000];
constexpr FastIoDigitTable() : num() {
for (int i = 0; i < 10000; ++i) {
int x = i;
for (int j = 3; j >= 0; --j) {
num[i * 4 + j] = char('0' + x % 10);
x /= 10;
}
}
}
};
struct Scanner {
static constexpr int BUFSIZE = 1 << 17;
static constexpr int OFFSET = 64;
char buf[BUFSIZE + 1];
int idx, size;
bool interactive;
Scanner() : idx(0), size(0), interactive(isatty(fileno(stdin))) {}
inline void load() {
int len = size - idx;
memmove(buf, buf + idx, len);
if (interactive) {
if (fgets(buf + len, BUFSIZE + 1 - len, stdin)) size = len + (int)strlen(buf + len);
else size = len;
} else {
size = len + (int)fread(buf + len, 1, BUFSIZE - len, stdin);
}
idx = 0;
buf[size] = 0;
}
inline void ensure() {
if (idx + OFFSET > size) load();
}
inline void ensure_interactive() {
if (idx == size) load();
}
inline char skip() {
if (interactive) {
ensure_interactive();
while (buf[idx] && buf[idx] <= ' ') {
++idx;
ensure_interactive();
}
return buf[idx++];
}
ensure();
while (buf[idx] && buf[idx] <= ' ') {
++idx;
ensure();
}
return buf[idx++];
}
template<class T, typename enable_if<is_integral<T>::value, int>::type = 0>
void read(T &x) {
if (interactive) {
char c = skip();
bool neg = false;
if constexpr (is_signed<T>::value) {
if (c == '-') {
neg = true;
ensure_interactive();
c = buf[idx++];
}
}
x = 0;
while (c >= '0') {
x = x * 10 + (c & 15);
ensure_interactive();
c = buf[idx++];
}
if constexpr (is_signed<T>::value) {
if (neg) x = -x;
}
return;
}
char c = skip();
bool neg = false;
if constexpr (is_signed<T>::value) {
if (c == '-') {
neg = true;
c = buf[idx++];
}
}
x = 0;
while (c >= '0') {
x = x * 10 + (c & 15);
c = buf[idx++];
}
if constexpr (is_signed<T>::value) {
if (neg) x = -x;
}
}
template<class T, typename enable_if<!is_integral<T>::value && !is_fastio_range<T>::value && !is_same<typename decay<T>::type, string>::value && has_fastio_value<T>::value, int>::type = 0>
void read(T &x) {
long long v;
read(v);
x = T(v);
}
template<class Head, class Next, class... Tail>
void read(Head &head, Next &next, Tail &...tail) {
read(head);
read(next, tail...);
}
template<class T, class U>
void read(pair<T, U> &p) {
read(p.first, p.second);
}
template<class T, typename enable_if<is_fastio_range<T>::value && !is_same<typename decay<T>::type, string>::value, int>::type = 0>
void read(T &a) {
for (auto &x : a) read(x);
}
void read(char &c) {
c = skip();
}
void read(string &s) {
s.clear();
if (interactive) {
ensure_interactive();
while (buf[idx] && buf[idx] <= ' ') {
++idx;
ensure_interactive();
}
while (true) {
int start = idx;
while (idx < size && buf[idx] > ' ') ++idx;
s.append(buf + start, idx - start);
if (idx < size) break;
load();
if (size == 0) break;
}
if (idx < size) ++idx;
return;
}
ensure();
while (buf[idx] && buf[idx] <= ' ') {
++idx;
ensure();
}
while (true) {
int start = idx;
while (idx < size && buf[idx] > ' ') ++idx;
s.append(buf + start, idx - start);
if (idx < size) break;
load();
}
if (idx < size) ++idx;
}
};
struct Printer {
static constexpr int BUFSIZE = 1 << 17;
static constexpr int OFFSET = 64;
char buf[BUFSIZE];
int idx;
bool interactive;
inline static constexpr FastIoDigitTable table{};
Printer() : idx(0), interactive(isatty(fileno(stdout))) {}
~Printer() { flush(); }
inline void flush() {
if (idx) {
fwrite(buf, 1, idx, stdout);
idx = 0;
}
}
inline void pc(char c) {
if (idx > BUFSIZE - OFFSET) flush();
buf[idx++] = c;
if (interactive && c == '\n') flush();
}
inline void print_range(const char *s, size_t n) {
size_t pos = 0;
while (pos < n) {
if (idx == BUFSIZE) flush();
size_t chunk = min(n - pos, (size_t)(BUFSIZE - idx));
memcpy(buf + idx, s + pos, chunk);
idx += (int)chunk;
pos += chunk;
}
}
void print(const char *s) {
print_range(s, strlen(s));
}
void print(const string &s) {
print_range(s.data(), s.size());
}
void print(char c) {
pc(c);
}
void print(bool b) {
pc(char('0' + (b ? 1 : 0)));
}
template<class T, typename enable_if<is_integral<T>::value && !is_same<T, bool>::value, int>::type = 0>
void print(T x) {
if (idx > BUFSIZE - 100) flush();
using U = typename make_unsigned<T>::type;
U y;
if constexpr (is_signed<T>::value) {
if (x < 0) {
buf[idx++] = '-';
y = U(0) - static_cast<U>(x);
} else {
y = static_cast<U>(x);
}
} else {
y = x;
}
if (y == 0) {
buf[idx++] = '0';
return;
}
static constexpr int TMP_SIZE = sizeof(U) * 10 / 4;
char tmp[TMP_SIZE];
int pos = TMP_SIZE;
while (y >= 10000) {
pos -= 4;
memcpy(tmp + pos, table.num + (y % 10000) * 4, 4);
y /= 10000;
}
if (y >= 1000) {
memcpy(buf + idx, table.num + (y << 2), 4);
idx += 4;
} else if (y >= 100) {
memcpy(buf + idx, table.num + (y << 2) + 1, 3);
idx += 3;
} else if (y >= 10) {
unsigned q = (unsigned(y) * 205) >> 11;
buf[idx] = char('0' + q);
buf[idx + 1] = char('0' + (unsigned(y) - q * 10));
idx += 2;
} else {
buf[idx++] = char('0' + y);
}
memcpy(buf + idx, tmp + pos, TMP_SIZE - pos);
idx += TMP_SIZE - pos;
}
template<class T, typename enable_if<!is_integral<T>::value && !is_fastio_range<T>::value && !is_same<typename decay<T>::type, string>::value && has_fastio_value<T>::value, int>::type = 0>
void print(const T &x) {
print(x.value());
}
template<class T, typename enable_if<is_fastio_range<T>::value && !is_same<typename decay<T>::type, string>::value, int>::type = 0>
void print(const T &a) {
bool first = true;
for (auto &&x : a) {
if (!first) pc(' ');
first = false;
print(x);
}
}
template<class T>
void println(const T &x) {
print(x);
pc('\n');
}
template<class Head, class... Tail>
void println(const Head &head, const Tail &...tail) {
print(head);
((pc(' '), print(tail)), ...);
pc('\n');
}
void println() {
pc('\n');
}
};
template<class T>
Scanner &operator>>(Scanner &in, T &x) {
in.read(x);
return in;
}
template<class T>
Printer &operator<<(Printer &out, const T &x) {
out.print(x);
return out;
}
/**
* @brief 高速入出力(Fast IO)
*/
#line 1 "graph/block_cut_tree.cpp"
using namespace std;
#line 1 "graph/biconnected_components.cpp"
class BiconnectedComponents {
vector<int> st;
void dfs(int i, int pe, int &pos){
ord[i] = low[i] = pos++;
for (auto &&e : G[i]) {
int j = e.first, id = e.second;
if(id == pe) continue;
if(ord[j] < ord[i]) st.emplace_back(id);
if(~ord[j]){
low[i] = min(low[i], ord[j]);
continue;
}
par[j] = i;
dfs(j, id, pos);
low[i] = min(low[i], low[j]);
if(ord[i] <= low[j]){
bcc_edges.emplace_back();
while(true){
int k = st.back();
st.pop_back();
bcc_edges.back().emplace_back(min(edges[k].first, edges[k].second), max(edges[k].first, edges[k].second));
if(k == id) break;
}
}
}
}
public:
vector<int> ord, low, par;
vector<pair<int, int>> edges;
vector<vector<pair<int, int>>> G;
vector<vector<pair<int, int>>> bcc_edges;
vector<vector<int>> bcc_vertices;
explicit BiconnectedComponents(int n): ord(n, -1), low(n), par(n, -1), G(n){}
void add_edge(int u, int v){
if(u != v){
int id = edges.size();
edges.emplace_back(u, v);
G[u].emplace_back(v, id);
G[v].emplace_back(u, id);
}
}
int build(){
int n = G.size(), pos = 0;
fill(ord.begin(), ord.end(), -1);
fill(par.begin(), par.end(), -1);
bcc_edges.clear();
bcc_vertices.clear();
st.clear();
for (int i = 0; i < n; ++i) {
if(ord[i] < 0) dfs(i, -1, pos);
}
vector<int> seen(n, -1);
bcc_vertices.reserve(bcc_edges.size());
for (int i = 0; i < (int)bcc_edges.size(); ++i) {
vector<int> now;
for (auto &&e : bcc_edges[i]) {
if(seen[e.first] != i){
seen[e.first] = i;
now.emplace_back(e.first);
}
if(seen[e.second] != i){
seen[e.second] = i;
now.emplace_back(e.second);
}
}
bcc_vertices.emplace_back(now);
}
for (int i = 0; i < n; ++i) {
if(G[i].empty()){
bcc_edges.emplace_back();
bcc_vertices.push_back({i});
}
}
return bcc_vertices.size();
}
};
/**
* @brief 二重連結成分分解(Biconnected Components)
*/
#line 4 "graph/block_cut_tree.cpp"
struct BlockCutTree {
int n, block_count;
BiconnectedComponents bcc;
vector<vector<int>> tree, nodes;
vector<int> id, rev;
vector<char> is_articulation;
explicit BlockCutTree(int n) : n(n), block_count(0), bcc(n), id(n, -1), is_articulation(n, 0) {}
void add_edge(int u, int v) {
bcc.add_edge(u, v);
}
int build() {
block_count = bcc.build();
vector<int> cnt(n);
for (auto &&vs : bcc.bcc_vertices) {
for (auto &&v : vs) ++cnt[v];
}
int m = block_count;
id.assign(n, -1);
is_articulation.assign(n, 0);
for (int v = 0; v < n; ++v) {
if (cnt[v] > 1) {
is_articulation[v] = 1;
id[v] = m++;
}
}
tree.assign(m, {});
nodes.assign(m, {});
rev.assign(m, -1);
for (int i = 0; i < block_count; ++i) {
nodes[i] = bcc.bcc_vertices[i];
for (auto &&v : bcc.bcc_vertices[i]) {
if (cnt[v] > 1) {
tree[i].push_back(id[v]);
tree[id[v]].push_back(i);
} else {
id[v] = i;
}
}
}
for (int v = 0; v < n; ++v) {
if (is_articulation[v]) {
nodes[id[v]].push_back(v);
rev[id[v]] = v;
}
}
return m;
}
};
/**
* @brief ブロックカット木(Block-Cut Tree)
*/
#line 1 "tree/hld.cpp"
class HeavyLightDecomposition {
void dfs_sz(int v){
int heavy = -1;
for (auto &&u : G[v]) {
if(u == par[v]) continue;
par[u] = v; dep[u] = dep[v] + 1;
dfs_sz(u);
sub_size[v] += sub_size[u];
if(heavy == -1 || sub_size[u] > sub_size[heavy]) heavy = u;
}
if (heavy != -1 && G[v][0] != heavy) {
for (auto &&u : G[v]) {
if (u == heavy) {
swap(u, G[v][0]);
break;
}
}
}
}
void dfs_hld(int v, int c, int &pos){
id[v] = pos++;
id_inv[id[v]]= v;
tree_id[v] = c;
for (auto &&u : G[v]) {
if(u == par[v]) continue;
head[u] = (u == G[v][0] ? head[v] : u);
dfs_hld(u, c, pos);
}
}
public:
int n;
vector<vector<int>> G;
vector<int> par, dep, sub_size, id, id_inv, tree_id, head;
explicit HeavyLightDecomposition(int n) : n(n), G(n), par(n), dep(n), sub_size(n, 1), id(n), id_inv(n), tree_id(n), head(n){}
explicit HeavyLightDecomposition(vector<vector<int>> &G) : n(G.size()), G(G), par(n), dep(n), sub_size(n, 1), id(n), id_inv(n), tree_id(n), head(n) {}
void add_edge(int u, int v){
G[u].emplace_back(v);
G[v].emplace_back(u);
}
void build(vector<int> roots = {0}){
fill(par.begin(), par.end(), -1);
fill(dep.begin(), dep.end(), 0);
fill(sub_size.begin(), sub_size.end(), 1);
int c = 0, pos = 0;
for (auto &&i : roots) {
dfs_sz(i);
head[i] = i;
dfs_hld(i, c++, pos);
}
}
int lca(int u, int v){
while(true){
if(id[u] > id[v]) swap(u, v);
if(head[u] == head[v]) return u;
v = par[head[v]];
}
}
int parent(int v) const {
return par[v];
}
int ancestor(int v, int k) {
if(dep[v] < k) return -1;
while(true) {
int u = head[v];
if(id[v] - k >= id[u]) return id_inv[id[v] - k];
k -= id[v]-id[u]+1;
v = par[u];
}
}
int distance(int u, int v){ return dep[u] + dep[v] - 2*dep[lca(u, v)]; }
pair<int, int> subtree(int v, bool edge = false) const {
return {id[v] + edge, id[v] + sub_size[v]};
}
template<typename F>
void add(int u, int v, const F &f, bool edge){
while (head[u] != head[v]){
if(id[u] > id[v]) swap(u, v);
f(id[head[v]], id[v]+1);
v = par[head[v]];
}
if(id[u] > id[v]) swap(u, v);
f(id[u]+edge, id[v]+1);
}
template<typename F>
void path(int u, int v, const F &f, bool edge = false){
add(u, v, f, edge);
}
template<typename F>
void apply_subtree(int v, const F &f, bool edge = false){
auto [l, r] = subtree(v, edge);
f(l, r);
}
template<typename T, typename Q, typename F>
T query(int u, int v, const T &e, const Q &q, const F &f, bool edge){
T l = e, r = e;
while(head[u] != head[v]){
if(id[u] > id[v]) swap(u, v), swap(l, r);
l = f(l, q(id[head[v]], id[v]+1));
v = par[head[v]];
}
if(id[u] > id[v]) swap(u, v), swap(l, r);
return f(q(id[u]+edge, id[v]+1), f(l, r));
}
template<typename T, typename Q, typename F>
T path_query(int u, int v, const T &e, const Q &q, const F &f, bool edge = false){
return query(u, v, e, q, f, edge);
}
template<typename T, typename QL, typename QR, typename F>
T query_order(int u, int v, const T &e, const QL &ql, const QR &qr, const F &f, bool edge){
T l = e, r = e;
while(head[u] != head[v]){
if(id[u] > id[v]) {
l = f(l, qr(id[head[u]], id[u]+1));
u = par[head[u]];
}else {
r = f(ql(id[head[v]], id[v]+1), r);
v = par[head[v]];
}
}
T mid = (id[u] > id[v] ? qr(id[v]+edge, id[u]+1) : ql(id[u]+edge, id[v]+1));
return f(f(l, mid), r);
}
template<typename T, typename QL, typename QR, typename F>
T path_query_ordered(int u, int v, const T &e, const QL &ql, const QR &qr, const F &f, bool edge = false){
return query_order(u, v, e, ql, qr, f, edge);
}
template<typename T, typename Q>
T subtree_query(int v, const Q &q, bool edge = false){
auto [l, r] = subtree(v, edge);
return q(l, r);
}
};
/**
* @brief HL分解(HL Decomposition)
*/
#line 14 "test/yuki1326_block_cut_tree.test.cpp"
int main() {
Scanner sc;
Printer pr;
int n, m;
sc.read(n, m);
BlockCutTree g(n);
for (int i = 0; i < m; ++i) {
int u, v;
sc.read(u, v);
--u, --v;
g.add_edge(u, v);
}
g.build();
HeavyLightDecomposition hld(g.tree);
hld.build();
vector<int> pref((int)g.tree.size());
for (int i = 0; i < (int)g.tree.size(); ++i) {
int v = hld.id_inv[i];
pref[v] = (g.rev[v] != -1);
if (hld.par[v] != -1) pref[v] += pref[hld.par[v]];
}
int q;
sc.read(q);
while (q--) {
int x, y;
sc.read(x, y);
--x, --y;
if (x == y) {
pr.println(0);
continue;
}
int u = g.id[x], v = g.id[y];
int a = hld.lca(u, v);
int ans = pref[u] + pref[v] - 2 * pref[a] + (g.rev[a] != -1);
if (g.is_articulation[x]) --ans;
if (g.is_articulation[y]) --ans;
pr.println(ans);
}
return 0;
}