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use graph_base::interfaces::graph::{Adjacency, AdjacencyInv, Degree, Directed, Graph};
use graph_base::interfaces::labeled::Labeled;
use std::collections::{HashSet, HashMap};
pub trait BoundedSimulation<'a> {
type Node: 'a;
fn get_bounded_simulation(&'a self, other: &'a Self) -> HashMap<&'a Self::Node, HashSet<&'a Self::Node>>;
}
pub trait Bounded<'a>: Graph<'a> {
fn get_bound(&'a self, u: &'a Self::Node, v: &'a Self::Node) -> usize;
}
impl<'a, 'b, T> BoundedSimulation<'a> for T
where
T: Graph<'a> + Bounded<'a> + Degree<'a> + Labeled<'a> + Adjacency<'a> + Degree<'a> + AdjacencyInv<'a> + Directed + 'b,
T::Node: 'a, T::Edge: 'a,
{
type Node = T::Node;
fn get_bounded_simulation(&'a self, other: &'a Self) -> HashMap<&'a Self::Node, HashSet<&'a Self::Node>> {
let adj_self = self.get_adj();
let adj_other = other.get_adj();
let adj_self_inv = self.get_adj_inv();
// let adj_other_inv = other.get_adj_inv();
// anc(get_bound(u_prime, u), u_prime, v) that returns v_prime in anc if:
// 1. label_same(u_prime, v_prime)
// 2. len(v_prime/.../v) <= get_bound(u_prime, u)
// dec(get_bound(u, u_prime), u_prime, v) that returns v_prime in dec if:
// 1. label_same(u_prime, v_prime)
// 2. len(v/.../v_prime) <= get_bound(u, u_prime)
// they are HashMap<(usize, &Node, &Node), HashSet<&Node>>
// We firstly compute the distance matrix M of (V_other, E_other)
let mut distance: HashMap<(&T::Node, &T::Node), usize> = HashMap::new();
for u in other.nodes() {
let mut queue: Vec<(&T::Node, usize)> = vec![(u, 0)];
let mut visited: HashSet<&T::Node> = HashSet::new();
visited.insert(u);
while !queue.is_empty() {
let (current, dist) = queue.remove(0);
distance.insert((u, current), dist);
for neighbor in other.get_post(&adj_other, current) {
if !visited.contains(neighbor) {
visited.insert(neighbor);
queue.push((neighbor, dist + 1));
}
}
}
}
let mut anc: HashMap<(usize, &T::Node, &T::Node), HashSet<&T::Node>> = HashMap::new();
let mut dec: HashMap<(usize, &T::Node, &T::Node), HashSet<&T::Node>> = HashMap::new();
// Then we compute anc and dec based on distance matrix
// compute anc
// anc(bound, u_prime, v) := {v_prime | label_same(u_prime, v_prime) and distance(v_prime, v) <= bound}
// where u_prime is node from self, v_prime and v are nodes from other
for u_prime in self.nodes() {
for u in self.get_post(&adj_self, u_prime) {
let bound = self.get_bound(u_prime, u);
for v in other.nodes() {
let mut anc_set: HashSet<&T::Node> = HashSet::new();
for v_prime in other.nodes() {
if self.label_same(u_prime, v_prime) {
if let Some(&dist) = distance.get(&(v_prime, v)) {
if dist <= bound {
anc_set.insert(v_prime);
}
}
}
}
anc.insert((bound, u_prime, v), anc_set);
}
}
}
// compute dec
// dec(bound, u_prime, v) := {v_prime | label_same(u_prime, v_prime) and distance(v, v_prime) <= bound}
// where u_prime is node from self, v_prime and v are nodes from other
// We need to compute dec for all possible (u', u) pairs to get all required bounds
for u in self.nodes() {
for u_prime in self.get_post(&adj_self, u) {
let bound = self.get_bound(u, u_prime);
for v in other.nodes() {
let mut dec_set: HashSet<&T::Node> = HashSet::new();
for v_prime in other.nodes() {
if self.label_same(u_prime, v_prime) {
if let Some(&dist) = distance.get(&(v, v_prime)) {
if dist <= bound {
dec_set.insert(v_prime);
}
}
}
}
dec.insert((bound, u_prime, v), dec_set);
}
}
}
let self_out_degree = self.get_out_degree();
let other_out_degree = other.get_out_degree();
// sim(u) := {v | v in V_other and label_same(u, v) and out_degree(v) != 0 if out_degree(u) != 0}
let mut sim = HashMap::new();
for u in self.nodes() {
let mut candidates: HashSet<&'a T::Node> = HashSet::new();
for v in other.nodes() {
if self.label_same(&u, v) {
if self.out_degree(&self_out_degree,&u) != 0 {
if other.out_degree(&other_out_degree,&v) != 0 {
candidates.insert(v);
}
} else {
candidates.insert(v);
}
}
}
sim.insert(u, candidates);
}
// presim(u) := {v | v in V_other and there NOT exists (u_prime, u) in E_self
// s.t. ((1) v_prime in sim(u), (2) label_same(u_prime, v), and (3) len(v/.../v_prime) <= get_bound(u_prime, u))}
let mut presim = HashMap::new();
for u in self.nodes() {
let mut candidates: HashSet<&'a T::Node> = HashSet::new();
'v_loop: for v in sim.get(&u).unwrap() {
if other.out_degree(&other_out_degree, v) == 0 {
continue;
}
// v 在 presim(u) 中，当且仅当：对所有 u' 都不存在这样的 v'
// 这里 u' 满足 (u_prime, u) in E_self，即 u' 是 u 的前驱
for u_prime in self.get_pre(&adj_self_inv, u) {
// 首先检查条件 (2)：label_same(u_prime, v)
// 如果 v 的标签不等于 u_prime 的标签，则条件 (2) 不满足，v 不可能被排除
if !self.label_same(u_prime, v) {
continue; // 这个 u_prime 无法排除 v，检查下一个 u_prime
}
let bound = self.get_bound(&u_prime, &u);
// 检查：是否存在 v' 满足条件
// (1) v' in sim(u)
// (2) label_same(u_prime, v) - 已经满足（见上面的检查）
// (3) len(v/.../v') <= bound (对应 dec)
if let Some(dec_set) = dec.get(&(bound, &u_prime, v)) {
// dec_set 包含所有标签为 u_prime 且距离 v 在 bound 内的节点
// 检查这些节点是否在 sim(u) 中
let has_match = dec_set.iter().any(|v_prime| {
sim.get(&u).unwrap().contains(v_prime)
});
// 如果存在这样的 v'，则 v 不在 presim(u) 中
if has_match {
continue 'v_loop;
}
}
// 如果 dec_set 不存在或为空，则不存在满足条件的 v'，继续检查下一个 u'
}
// 所有 u' 都不存在满足条件的 v'，v 在 presim(u) 中
candidates.insert(v);
}
presim.insert(u, candidates);
}
// while (there exists a node u ∈ V_self with premv(u) != ∅) do
// for (each (u′, u) ∈ E_self and each z ∈ premv(u) ∩ sim(u′)) do
// sim(u′) := sim(u′) \ {z};
// if (sim(u′) = ∅) then return ∅;
// for each u′′ with (u′′, u′) ∈ E_self do
// for (z′ ∈ anc(get_bound(u′′, u′), u′′, z) ∧ z′ /∈ premv(u′)) do
// if (dec(get_bound(u′′, u′), u′, z′) ∩ sim(u′) = ∅)
// then premv(u′) := premv(u′) ∪ {z′};
// premv(u) := ∅;
loop {
// 1. 找到一个 presim 非空的节点 u，如果没有则退出
let Some(u) = self.nodes().find(|node| !presim.get(node).unwrap().is_empty()) else {
break;
};
// 2. 提前复制 premv_u，避免后续借用冲突
let premv_u = presim.get(&u).unwrap().clone();
// 3. 收集所有 u 的前驱节点 u_prime，即边 (u_prime, u)
let u_primes: Vec<_> = self.get_pre(&adj_self_inv, &u).collect();
for u_prime in u_primes {
// 4. 提前收集 sim(u_prime) 和 premv_u 的交集
let sim_u_prime = sim.get(&u_prime).unwrap();
let to_remove: Vec<_> = premv_u.intersection(sim_u_prime).cloned().collect();
for z in to_remove {
// 5. 现在可以安全地修改 sim
sim.get_mut(&u_prime).unwrap().remove(&z);
if sim.get(&u_prime).unwrap().is_empty() {
return HashMap::new();
}
// 6. 收集 u_prime 的前驱节点 u_double_prime，即边 (u_double_prime, u_prime)
let u_double_primes: Vec<_> = self.get_pre(&adj_self_inv, &u_prime).collect();
// 7. 收集所有需要更新的 (u_double_prime, z_prime) 对
let mut updates: Vec<(&T::Node, &T::Node)> = Vec::new();
// 收集当前 presim(u_prime) 的值，用于检查 z' /∈ presim(u′)
let presim_u_prime = presim.get(&u_prime).unwrap().clone();
for u_double_prime in u_double_primes {
let bound = self.get_bound(&u_double_prime, &u_prime);
if let Some(anc_set) = anc.get(&(bound, &u_double_prime, &z)) {
// 收集 anc_set 到临时变量
let anc_vec: Vec<_> = anc_set.iter().cloned().collect();
// 过滤出满足条件的 z_prime: z' ∈ anc(...) ∧ z' /∈ presim(u′)
for z_prime in anc_vec.iter() {
if !presim_u_prime.contains(z_prime) {
// 检查 dec(...) ∩ sim(u') 是否为空
if let Some(dec_set) = dec.get(&(bound, &u_prime, z_prime)) {
let sim_u_prime_set = sim.get(&u_prime).unwrap();
let has_intersection = dec_set.iter().any(|v| sim_u_prime_set.contains(v));
if !has_intersection {
updates.push((u_double_prime, *z_prime));
}
}
}
}
}
}
// 8. 批量更新 presim(u_double_prime)
for (u_double_prime, z_prime) in updates {
presim.get_mut(&u_double_prime).unwrap().insert(z_prime);
}
}
}
// 9. 清空 presim(u)
presim.get_mut(&u).unwrap().clear();
}
sim
}
}