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dijkstra.lib.cpp
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dijkstra.lib.cpp
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/**
* Dijkstra
*/
template <typename T>
struct dijkstra_graph
{
public:
using Vertex = std::pair<T, long long>;
using Edge = std::pair<T, long long>;
long long N;
std::vector<std::vector<Edge>> G;
std::vector<T> d;
std::vector<long long> p;
const long long _inf = 1LL << 60;
dijkstra_graph(long long n)
: N(n + 1),
G(n + 1),
d(n + 1),
p(n + 1)
{}
void add_edge(long long from, long long to, T cost)
{
G[from].emplace_back(Edge(to, cost));
}
std::vector<T> search(long long s)
{
std::fill(d.begin(), d.end(), _inf);
std::fill(p.begin(), p.end(), -1);
d[s] = 0;
std::priority_queue<Vertex, std::vector<Vertex>, std::greater<Vertex>> pq;
pq.push(Vertex(s, 0));
while (pq.size()) {
long long v = pq.top().first;
long long dd = pq.top().second;
pq.pop();
if (d[v] < dd) continue;
for (auto e : G[v]) {
long long nv = e.first;
long long c = e.second;
if (d[nv] > d[v] + c) {
d[nv] = d[v] + c;
p[nv] = v;
pq.push(Vertex(nv, d[nv]));
}
}
}
return d;
}
T dist(long long i) const
{
return d.at(i);
}
std::vector<long long> shortest_path(long long t)
{
std::vector<long long> res;
long long cur = t;
while (cur != -1) {
res.emplace_back(cur);
cur = p[cur];
}
std::reverse(res.begin(), res.end());
return res;
}
};
/**
* End
*/